Im not sure exactly what version i have but if I were to guess Id say 11.something
major.minor version 51.0
at cpw.mods.fml.common.Loader.load(Loader.java:436)
at cpw.mods.fml.common.Loader.loadMods(Loader.java:606)
at cpw.mods.fml.server.FMLBukkitHandler.onPreLoad(FMLBukkitHandler.java:134)
at net.minecraft.server.MinecraftServer.init(MinecraftServer.java:135)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:438)
at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)
Caused by: cpw.mods.fml.common.LoaderException: java.lang.UnsupportedClassVersionError: net/minecraft/server/mod_NetherOres : Unsupported major.minor version 51.0
at cpw.mods.fml.common.Loader.loadModClass(Loader.java:527)
at cpw.mods.fml.common.Loader.attemptFileLoad(Loader.java:562)
at cpw.mods.fml.common.Loader.load(Loader.java:419)
... 5 more
Caused by: java.lang.UnsupportedClassVersionError: net/minecraft/server/mod_NetherOres : Unsupported major.minor version 51.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(ClassLoader.java:631)
at java.lang.ClassLoader.defineClass(ClassLoader.java:615)
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$1.run(URLClassLoader.java:197)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:295)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:247)
at cpw.mods.fml.common.Loader.loadModClass(Loader.java:494)
... 7 more
>stop
00:46:13 [iNFO] Stopping server
00:46:13 [sEVERE] java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
00:46:13 [sEVERE] at java.util.ArrayList.RangeCheck(ArrayList.java:547)
00:46:13 [sEVERE] at java.util.ArrayList.get(ArrayList.java:322)
00:46:13 [sEVERE] at net.minecraft.server.MinecraftServer.stop(MinecraftServer.java:424)
00:46:13 [sEVERE] at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:497)
00:46:13 [sEVERE] at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)