Ex Astris doesn't like TE4 when Redstone Arsenal is installed:
---- Minecraft Crash Report ----
// Why did you do that?

Time: 01.04.15 16:16
Description: There was a severe problem during mod loading that has caused the game to fail

cpw.mods.fml.common.LoaderException: java.lang.NoClassDefFoundError: ExAstris/Item/ItemHammerRF
at cpw.mods.fml.common.LoadController.transition(LoadController.java:162)
at cpw.mods.fml.common.Loader.preinitializeMods(Loader.java:515)
at cpw.mods.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:239)
at com.creativemd.minecraftloader.ClientHelper.startGame(ClientHelper.java:260)
at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java)
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:867)
at net.minecraft.client.main.Main.main(SourceFile:148)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at net.minecraft.launchwrapper.Launch.launch(Launch.java:135)
at net.minecraft.launchwrapper.Launch.main(Launch.java:28)
Caused by: java.lang.NoClassDefFoundError: ExAstris/Item/ItemHammerRF
at ExAstris.ExAstrisItem.registerItems(ExAstrisItem.java:78)
at ExAstris.ExAstris.PreInitialize(ExAstris.java:54)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at cpw.mods.fml.common.FMLModContainer.handleModStateEvent(FMLModContainer.java:513)
at sun.reflect.GeneratedMethodAccessor4.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.google.common.eventbus.EventSubscriber.handleEvent(EventSubscriber.java:74)
at com.google.common.eventbus.SynchronizedEventSubscriber.handleEvent(SynchronizedEventSubscriber.java:47)
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:322)
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:304)
at com.google.common.eventbus.EventBus.post(EventBus.java:275)
at cpw.mods.fml.common.LoadController.sendEventToModContainer(LoadController.java:208)
at sun.reflect.GeneratedMethodAccessor3.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.creativemd.minecraftloader.MinecraftDummyContainer.callMethod(MinecraftDummyContainer.java:209)
at com.creativemd.minecraftloader.MinecraftDummyContainer.onModEvent(MinecraftDummyContainer.java:201)
at cpw.mods.fml.common.LoadController.propogateStateMessage(LoadController.java)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.google.common.eventbus.EventSubscriber.handleEvent(EventSubscriber.java:74)
at com.google.common.eventbus.SynchronizedEventSubscriber.handleEvent(SynchronizedEventSubscriber.java:47)
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:322)
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:304)
at com.google.common.eventbus.EventBus.post(EventBus.java:275)
at cpw.mods.fml.common.LoadController.distributeStateMessage(LoadController.java:118)
at cpw.mods.fml.common.Loader.preinitializeMods(Loader.java:513)
... 11 more
Caused by: java.lang.ClassNotFoundException: ExAstris.Item.ItemHammerRF
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:191)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
... 44 more
Caused by: java.lang.NoClassDefFoundError: redstonearsenal/item/tool/ItemToolRF
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknown Source)
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:182)
... 46 more
Caused by: java.lang.ClassNotFoundException: redstonearsenal.item.tool.ItemToolRF
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:101)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
... 50 more

A detailed walkthrough of the error, its code path and all known details is as follows:

-- System Details --
Details:
Minecraft Version: 1.7.10
Operating System: Windows 8.1 (amd64) version 6.3
Java Version: 1.8.0_31, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 1800963504 bytes (1717 MB) / 2134114304 bytes (2035 MB) up to 2134114304 bytes (2035 MB)
JVM Flags: 12 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M -Xmx2G -Xms2G -XX:PermSize=256m -XX:MaxPermSize=512m -XX:+AggressiveOpts -XX:+UseFastAccessorMethods
AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
FML: MCP v9.05 FML v7.10.85.1291 Minecraft Forge 10.13.2.1291 70 mods loaded, 70 mods active
mcp{9.05} Minecraft Coder Pack Unloaded->Constructed->Pre-initialized
FML{7.10.85.1291} Forge Mod Loader Unloaded->Constructed->Pre-initialized
Forge{10.13.2.1291} Minecraft Forge Unloaded->Constructed->Pre-initialized
CodeChickenCore{1.0.4.35} CodeChicken Core Unloaded->Constructed->Pre-initialized
ExtraFixes{0.1.1} Extra Fixes Unloaded->Constructed->Pre-initialized
minecraftloader{0.1} MinecraftLoader Unloaded->Constructed->Pre-initialized
MobiusCore{1.2.4} MobiusCore Unloaded->Constructed->Pre-initialized
NotEnoughItems{1.0.4.95} Not Enough Items Unloaded->Constructed->Pre-initialized
OpenEye{0.6} OpenEye Unloaded->Constructed->Pre-initialized
OpenModsCore{0.6} OpenModsCore Unloaded->Constructed->Pre-initialized
{000} CoFH ASM Data Initialization Unloaded->Constructed->Pre-initialized
lucky{5.1.0} Lucky Block Unloaded->Constructed->Pre-initialized
ActuallyAdditions{1.7.10-0.0.3.3} Actually Additions Unloaded->Constructed->Pre-initialized
Baubles{1.0.1.10} Baubles Unloaded->Constructed->Pre-initialized
betterstorage{0.11.3.123} BetterStorage Unloaded->Constructed->Pre-initialized
CoFHCore{1.7.10R3.0.0RC7} CoFH Core Unloaded->Constructed->Pre-initialized
BuildCraft|Core{7.0.0} BuildCraft Unloaded->Constructed->Pre-initialized
BuildCraft|Silicon{7.0.0} BC Silicon Unloaded->Constructed->Pre-initialized
BuildCraft|Transport{7.0.0} BC Transport Unloaded->Constructed->Pre-initialized
BuildCraft|Builders{7.0.0} BC Builders Unloaded->Constructed->Pre-initialized
BuildCraft|Robotics{7.0.0} BuildCraft Robotics Unloaded->Constructed->Pre-initialized
BuildCraft|Energy{7.0.0} BC Energy Unloaded->Constructed->Pre-initialized
BuildCraft|Factory{7.0.0} BC Factory Unloaded->Constructed->Pre-initialized
Railcraft{9.5.0.0} Railcraft Unloaded->Constructed->Pre-initialized
BurpTechCore{1.7.10.56} BurpTech Unloaded->Constructed->Pre-initialized
CarpentersBlocks{3.3.4.4} [Carpenter's Blocks](Carpenter's Blocks v3.3.4.4 - MC 1.7.10.jar) Unloaded->Constructed->Pre-initialized
CartLivery{0.11.1} Cart Livery Unloaded->Constructed->Pre-initialized
colourfulportalsmod{1.4.2} Colourful Portals Unloaded->Constructed->Pre-initialized
cookiecore{1.3.1} Cookie Core Unloaded->Constructed->Pre-initialized
EnderStorage{1.4.5.30} EnderStorage Unloaded->Constructed->Pre-initialized
enderutilities{0.4.0-beta-1} Ender Utilities Unloaded->Constructed->Pre-initialized
exnihilo{1.37} Ex Nihilo Unloaded->Constructed->Pre-initialized
ThermalFoundation{1.7.10R1.0.0RC7} Thermal Foundation Unloaded->Constructed->Pre-initialized
ThermalExpansion{1.7.10R4.0.0RC7} Thermal Expansion Unloaded->Constructed->Pre-initialized
RedstoneArsenal{1.7.10R1.1.0RC7} Redstone Arsenal Unloaded->Constructed->Pre-initialized
Mantle{1.7.10-0.3.2.jenkins184} Mantle Unloaded->Constructed->Pre-initialized
TConstruct{1.7.10-1.8.3.build919} Tinkers' Construct Unloaded->Constructed->Pre-initialized
TSteelworks{1.7.10-1.1.0} Tinkers' Steelworks Unloaded->Constructed->Pre-initialized
exastris{1.15} Ex Astris Unloaded->Constructed->Errored
ForgeMultipart{1.1.1.326} Forge Multipart Unloaded->Constructed->Pre-initialized
ExtraUtilities{1.2.2} Extra Utilities Unloaded->Constructed->Pre-initialized
FastCraft{1.21} FastCraft Unloaded->Constructed->Pre-initialized
McMultipart{1.1.1.326} Minecraft Multipart Plugin Unloaded->Constructed->Pre-initialized
ganysend{1.8.8} [Gany's End](Ganys End-1.8.8.jar) Unloaded->Constructed->Pre-initialized
ganysnether{1.7.8} [Gany's Nether](Ganys Nether-1.7.8.jar) Unloaded->Constructed->Pre-initialized
ganyssurface{1.9.6} [Gany's Surface](Ganys Surface-1.9.6.jar) Unloaded->Constructed->Pre-initialized
JABBA{1.2.1} JABBA Unloaded->Constructed->Pre-initialized
legendgear{2.b.2.1} LegendGear 2 Unloaded->Constructed->Pre-initialized
NEIAddons{1.12.4.16} NEI Addons Unloaded->Constructed->Pre-initialized
NEIAddons|Botany{1.12.4.16} NEI Addons: Botany Unloaded->Constructed->Pre-initialized
NEIAddons|Forestry{1.12.4.16} NEI Addons: Forestry Unloaded->Constructed->Pre-initialized
NEIAddons|CraftingTables{1.12.4.16} NEI Addons: Crafting Tables Unloaded->Constructed->Pre-initialized
NEIAddons|ExNihilo{1.12.4.16} NEI Addons: Ex Nihilo Unloaded->Constructed->Pre-initialized
neiintegration{1.0.7} NEI Integration Unloaded->Constructed->Pre-initialized
OpenMods{0.6} OpenMods Unloaded->Constructed->Pre-initialized
OpenBlocks{1.3} OpenBlocks Unloaded->Constructed->Pre-initialized
MapWriter{2.1.2} MapWriter Unloaded->Constructed->Pre-initialized
Opis{1.2.4} Opis Unloaded->Constructed->Pre-initialized
mod_pndc{0.1} Peaceful Nights, Dangerous Caves Unloaded->Constructed->Pre-initialized
quiverchevsky{b97} QuiverBow Unloaded->Constructed->Pre-initialized
quivermobchevsky{b12} QuiverMob Unloaded->Constructed->Pre-initialized
RandomThings{2.2.4} Random Things Unloaded->Constructed->Pre-initialized
RIO{2.2} RemoteIO Unloaded->Constructed->Pre-initialized
Sampler{1.33} Sampler Unloaded->Constructed->Pre-initialized
screenshots{1.0.0} Screenshots Enhanced Unloaded->Constructed->Pre-initialized
simplyjetpacks{1.4.1} Simply Jetpacks Unloaded->Constructed->Pre-initialized
ThermalDynamics{1.7.10R1.0.0RC7} Thermal Dynamics Unloaded->Constructed->Pre-initialized
Translocator{1.1.1.14} Translocator Unloaded->Constructed->Pre-initialized
aobd{2.5.0} Another One Bites The Dust Unloaded->Constructed->Pre-initialized
ForgeMicroblock{1.1.1.326} Forge Microblocks Unloaded->Constructed->Pre-initialized
OpenModsLib crash transformers: [stencil_patches:FINISHED],[movement_callback:FINISHED],[map_gen_fix:ENABLED],[gl_capabilities_hook:FINISHED],[player_render_hook:FINISHED]
CoFHCore: -[1.7.10]3.0.0RC7-211
ThermalFoundation: -[1.7.10]1.0.0RC7-62
ThermalExpansion: -[1.7.10]4.0.0RC7-141
RedstoneArsenal: -[1.7.10]1.1.0RC7-65
Mantle Environment: Environment healthy.
TConstruct Environment: Environment healthy.
ThermalDynamics: -[1.7.10]1.0.0RC7-98
Stencil buffer state: Function set: GL30, pool: forge, bits: 8

You are using a very old version of Ex Nihilo/Ex Astris. Please update both.

Ex Nihilo: http://minecraft.curseforge.com/mc-mods/221696-ex-nihilo/files
Ex Astris: http://minecraft.curseforge.com/mc-mods/226340-ex-astris/files

I'll try
UPDATE: It worked! Thank you!