[21:40:50] [main/INFO] [LaunchWrapper]: Loading tweak class name cpw.mods.fml.common.launcher.FMLTweaker
[21:40:50] [main/INFO] [LaunchWrapper]: Using primary tweak class name cpw.mods.fml.common.launcher.FMLTweaker
[21:40:50] [main/INFO] [LaunchWrapper]: Calling tweak class cpw.mods.fml.common.launcher.FMLTweaker
[21:40:50] [main/INFO] [FML]: Forge Mod Loader version 7.2.217.1147 for Minecraft 1.7.2 loading
[21:40:50] [main/INFO] [FML]: Java is Java HotSpot(TM) 64-Bit Server VM, version 1.6.0_65, running on Mac OS X:x86_64:10.9.5, installed at /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home
java.lang.UnsupportedClassVersionError: de/sanandrew/core/manpack/init/ManPackLoadingPlugin : Unsupported major.minor version 51.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(ClassLoader.java:637)
at java.lang.ClassLoader.defineClass(ClassLoader.java:621)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:283)
at java.net.URLClassLoader.access$000(URLClassLoader.java:58)
at java.net.URLClassLoader$1.run(URLClassLoader.java:197)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:115)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:249)
at cpw.mods.fml.relauncher.CoreModManager.loadCoreMod(CoreModManager.java:383)
at cpw.mods.fml.relauncher.CoreModManager.discoverCoreMods(CoreModManager.java:312)
at cpw.mods.fml.relauncher.CoreModManager.handleLaunch(CoreModManager.java:214)
at cpw.mods.fml.relauncher.FMLLaunchHandler.setupHome(FMLLaunchHandler.java:90)
at cpw.mods.fml.relauncher.FMLLaunchHandler.setupClient(FMLLaunchHandler.java:67)
at cpw.mods.fml.relauncher.FMLLaunchHandler.configureForClientLaunch(FMLLaunchHandler.java:34)
at cpw.mods.fml.common.launcher.FMLTweaker.injectIntoClassLoader(FMLTweaker.java:124)
at net.minecraft.launchwrapper.Launch.launch(Launch.java:114)
at net.minecraft.launchwrapper.Launch.main(Launch.java:28)
[21:40:50] [main/ERROR] [FML]: An error occurred trying to configure the minecraft home at /Users/Sam/Library/Application Support/minecraft for Forge Mod Loader
java.lang.UnsupportedClassVersionError: de/sanandrew/core/manpack/init/ManPackLoadingPlugin : Unsupported major.minor version 51.0
at java.lang.ClassLoader.defineClass1(Native Method) ~[?:1.6.0_65]
at java.lang.ClassLoader.defineClassCond(ClassLoader.java:637) ~[?:1.6.0_65]
at java.lang.ClassLoader.defineClass(ClassLoader.java:621) ~[?:1.6.0_65]
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141) ~[?:1.6.0_65]
at java.net.URLClassLoader.defineClass(URLClassLoader.java:283) ~[?:1.6.0_65]
at java.net.URLClassLoader.access$000(URLClassLoader.java:58) ~[?:1.6.0_65]
at java.net.URLClassLoader$1.run(URLClassLoader.java:197) ~[?:1.6.0_65]
at java.security.AccessController.doPrivileged(Native Method) ~[?:1.6.0_65]
at java.net.URLClassLoader.findClass(URLClassLoader.java:190) ~[?:1.6.0_65]
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:115) ~[launchwrapper-1.9.jar:?]
at java.lang.ClassLoader.loadClass(ClassLoader.java:306) ~[?:1.6.0_65]
at java.lang.ClassLoader.loadClass(ClassLoader.java:247) ~[?:1.6.0_65]
at java.lang.Class.forName0(Native Method) ~[?:1.6.0_65]
at java.lang.Class.forName(Class.java:249) ~[?:1.6.0_65]
at cpw.mods.fml.relauncher.CoreModManager.loadCoreMod(CoreModManager.java:383) ~[forge-1.7.2-10.12.2.1147.jar:?]
at cpw.mods.fml.relauncher.CoreModManager.discoverCoreMods(CoreModManager.java:312) ~[forge-1.7.2-10.12.2.1147.jar:?]
at cpw.mods.fml.relauncher.CoreModManager.handleLaunch(CoreModManager.java:214) ~[forge-1.7.2-10.12.2.1147.jar:?]
at cpw.mods.fml.relauncher.FMLLaunchHandler.setupHome(FMLLaunchHandler.java:90) [forge-1.7.2-10.12.2.1147.jar:?]
at cpw.mods.fml.relauncher.FMLLaunchHandler.setupClient(FMLLaunchHandler.java:67) [forge-1.7.2-10.12.2.1147.jar:?]
at cpw.mods.fml.relauncher.FMLLaunchHandler.configureForClientLaunch(FMLLaunchHandler.java:34) [forge-1.7.2-10.12.2.1147.jar:?]
at cpw.mods.fml.common.launcher.FMLTweaker.injectIntoClassLoader(FMLTweaker.java:124) [forge-1.7.2-10.12.2.1147.jar:?]
at net.minecraft.launchwrapper.Launch.launch(Launch.java:114) [launchwrapper-1.9.jar:?]
at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.9.jar:?]
Exception in thread "main" java.lang.UnsupportedClassVersionError: de/sanandrew/core/manpack/init/ManPackLoadingPlugin : Unsupported major.minor version 51.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(ClassLoader.java:637)
at java.lang.ClassLoader.defineClass(ClassLoader.java:621)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:283)
at java.net.URLClassLoader.access$000(URLClassLoader.java:58)
at java.net.URLClassLoader$1.run(URLClassLoader.java:197)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:115)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:249)
at cpw.mods.fml.relauncher.CoreModManager.loadCoreMod(CoreModManager.java:383)
at cpw.mods.fml.relauncher.CoreModManager.discoverCoreMods(CoreModManager.java:312)
at cpw.mods.fml.relauncher.CoreModManager.handleLaunch(CoreModManager.java:214)
at cpw.mods.fml.relauncher.FMLLaunchHandler.setupHome(FMLLaunchHandler.java:90)
at cpw.mods.fml.relauncher.FMLLaunchHandler.setupClient(FMLLaunchHandler.java:67)
at cpw.mods.fml.relauncher.FMLLaunchHandler.configureForClientLaunch(FMLLaunchHandler.java:34)
at cpw.mods.fml.common.launcher.FMLTweaker.injectIntoClassLoader(FMLTweaker.java:124)
at net.minecraft.launchwrapper.Launch.launch(Launch.java:114)
at net.minecraft.launchwrapper.Launch.main(Launch.java:28)
This is the screen i get when it crashes

i have the most recent version of everything (forge is the most recent 1.7.10)

i am on OSX

I AM ON JAVA 8

Please answer it soon this is the first mod i ever had and i want to see how far it has progressed.

are you sure all mods you are using with the core are at the current version and that the core is at the current version?

21:40:50] [main/INFO] [FML]: Java is Java HotSpot(TM) 64-Bit Server VM, version 1.6.0_65, running on Mac OS X:x86_64:10.9.5, installed at /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home
java.lang.UnsupportedClassVersionError: de/sanandrew/core/manpack/init/ManPackLoadingPlugin : Unsupported major.minor version 51.0

Use Java 7
See #23