I have tried everything i could. I have been trying to build a modpack, and this weird thing keeps happening when i have ex astris! I have tried removing all other mods besides ex nihilo & ex astris, but still a crash! someone please help...

CRASH REPORT:

B#301] [15:54:03] [Client thread/INFO] [STDOUT]: [net.minecraft.client.Minecraft:func_71377_b:349]: ---- Minecraft Crash Report ----
[B#301] // Who set us up the TNT?
[B#301]
[B#301] Time: 5/14/15 3:54 PM
[B#301] Description: There was a severe problem during mod loading that has caused the game to fail
[B#301]
[B#301] cpw.mods.fml.common.LoaderException: java.lang.ClassNotFoundException: ExAstris.ExAstris
[B#301] at cpw.mods.fml.common.LoadController.transition(LoadController.java:163)
[B#301] at cpw.mods.fml.common.Loader.loadMods(Loader.java:522)
[B#301] at cpw.mods.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:206)
[B#301] at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:480)
[B#301] at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:878)
[B#301] at net.minecraft.client.main.Main.main(SourceFile:148)
[B#301] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[B#301] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
[B#301] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
[B#301] at java.lang.reflect.Method.invoke(Method.java:597)
[B#301] at net.minecraft.launchwrapper.Launch.launch(Launch.java:135)
[B#301] at net.minecraft.launchwrapper.Launch.main(Launch.java:28)
[B#301] Caused by: java.lang.ClassNotFoundException: ExAstris.ExAstris
[B#301] at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:191)
[B#301] at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
[B#301] at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
[B#301] at cpw.mods.fml.common.ModClassLoader.loadClass(ModClassLoader.java:58)
[B#301] at java.lang.Class.forName0(Native Method)
[B#301] at java.lang.Class.forName(Class.java:249)
[B#301] at cpw.mods.fml.common.FMLModContainer.constructMod(FMLModContainer.java:440)
[B#301] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[B#301] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
[B#301] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
[B#301] at java.lang.reflect.Method.invoke(Method.java:597)
[B#301] at com.google.common.eventbus.EventSubscriber.handleEvent(EventSubscriber.java:74)
[B#301] at com.google.common.eventbus.SynchronizedEventSubscriber.handleEvent(SynchronizedEventSubscriber.java:47)
[B#301] at com.google.common.eventbus.EventBus.dispatch(EventBus.java:322)
[B#301] at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:304)
[B#301] at com.google.common.eventbus.EventBus.post(EventBus.java:275)
[B#301] at cpw.mods.fml.common.LoadController.sendEventToModContainer(LoadController.java:212)
[B#301] at cpw.mods.fml.common.LoadController.propogateStateMessage(LoadController.java:190)
[B#301] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[B#301] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
[B#301] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
[B#301] at java.lang.reflect.Method.invoke(Method.java:597)
[B#301] at com.google.common.eventbus.EventSubscriber.handleEvent(EventSubscriber.java:74)
[B#301] at com.google.common.eventbus.SynchronizedEventSubscriber.handleEvent(SynchronizedEventSubscriber.java:47)
[B#301] at com.google.common.eventbus.EventBus.dispatch(EventBus.java:322)
[B#301] at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:304)
[B#301] at com.google.common.eventbus.EventBus.post(EventBus.java:275)
[B#301] at cpw.mods.fml.common.LoadController.distributeStateMessage(LoadController.java:119)
[B#301] at cpw.mods.fml.common.Loader.loadMods(Loader.java:511)
[B#301] ... 10 more
[B#301] Caused by: java.lang.UnsupportedClassVersionError: ExAstris/ExAstris : Unsupported major.minor version 51.0
[B#301] at java.lang.ClassLoader.defineClass1(Native Method)
[B#301] at java.lang.ClassLoader.defineClassCond(ClassLoader.java:637)
[B#301] at java.lang.ClassLoader.defineClass(ClassLoader.java:621)
[B#301] at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
[B#301] at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:182)
[B#301] ... 38 more
[B#301]
[B#301]
[B#301] A detailed walkthrough of the error, its code path and all known details is as follows:
[B#301] ---------------------------------------------------------------------------------------
[B#301]
[B#301] -- System Details --
[B#301] Details:
[B#301] Minecraft Version: 1.7.10
[B#301] Operating System: Mac OS X (x86_64) version 10.10.3
[B#301] Java Version: 1.6.0_65, Apple Inc.
[B#301] Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Apple Inc.
[B#301] Memory: 42180472 bytes (40 MB) / 140709888 bytes (134 MB) up to 4286251008 bytes (4087 MB)
[B#301] JVM Flags: 2 total; -Xmx4096m -XX:MaxPermSize=256m
[B#301] AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
[B#301] IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
[B#301] FML: MCP v9.05 FML v7.10.141.1403 Minecraft Forge 10.13.3.1403 5 mods loaded, 5 mods active
[B#301] mcp{9.05} Minecraft Coder Pack Unloaded->Constructed
[B#301] FML{7.10.141.1403} Forge Mod Loader Unloaded->Constructed
[B#301] Forge{10.13.3.1403} Minecraft Forge Unloaded->Constructed
[B#301] exnihilo{1.37} Ex Nihilo Unloaded->Constructed
[B#301] exastris{MC1.7.10-1.16-35} Ex Astris Unloaded->Errored
[B#301] GL info: ' Vendor: 'ATI Technologies Inc.' Version: '2.1 ATI-1.32.20' Renderer: 'ATI Radeon HD 5670 OpenGL Engine'
[B#301] [15:54:03] [Client thread/INFO] [STDOUT]: [net.minecraft.client.Minecraft:func_71377_b:359]: #@!@# Game crashed! Crash report saved to: #@!@# /Users/boysCPU/Library/Application Support/technic/modpacks/wafflez-in-da-sky/crash-reports/crash-2015-05-14_15.54.03-client.txt

Appears ExAstris is not compatible with java 6, this is a bug and should be fixed. For now you can fix your issue by installing java 7.

Java 7 compliance (at least at compiletime) is required for Tinkers Steelworks API. This is probably still my fault, but I'm bad at versioning.

But...you have the TSteelworks API as compiled class files...