Unsupported Class Version (Server)

[WlkCz]

Launcher/pack Version: Tekkit_Server_3.0.3

Operating System: Windows 7 64bit

Version of Java: Java 6 Update 31 (64-bit); Java SE Development Kit 6 Update 31 (64-bit); Java 7 Update 4

Description of Problem: Server error appears when server starts.

Error Messages:

C:\TekkitServer3>java -Xmx3G -Xms2G -jar Tekkit.jar nogui

182 recipes

27 achievements

23:28:18 [iNFO] Starting minecraft server version 1.2.5

23:28:18 [iNFO] Forge Mod Loader version @MAJOR@.@MINOR@.@REV@.@BUILD@ for Minec

raft @MCVERSION@ loading

23:28:18 [iNFO] Loading mods from C:\TekkitServer3\mods

23:28:18 [sEVERE] java.lang.UnsupportedClassVersionError: net/minecraft/server/m

od_NetherOres : Unsupported major.minor version 51.0

23:28:18 [sEVERE]    at java.lang.ClassLoader.defineClass1(Native Method)

23:28:18 [sEVERE]    at java.lang.ClassLoader.defineClassCond(Unknown Source)



23:28:18 [sEVERE]    at java.lang.ClassLoader.defineClass(Unknown Source)

23:28:18 [sEVERE]    at java.security.SecureClassLoader.defineClass(Unknown S

ource)

23:28:18 [sEVERE]    at java.net.URLClassLoader.defineClass(Unknown Source)

23:28:18 [sEVERE]    at java.net.URLClassLoader.access$000(Unknown Source)

23:28:18 [sEVERE]    at java.net.URLClassLoader$1.run(Unknown Source)

23:28:18 [sEVERE]    at java.security.AccessController.doPrivileged(Native Me

thod)

23:28:18 [sEVERE]    at java.net.URLClassLoader.findClass(Unknown Source)

23:28:18 [sEVERE]    at java.lang.ClassLoader.loadClass(Unknown Source)

23:28:18 [sEVERE]    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown So

urce)

23:28:18 [sEVERE]    at java.lang.ClassLoader.loadClass(Unknown Source)

23:28:18 [sEVERE]    at java.lang.ClassLoader.loadClass(Unknown Source)

23:28:18 [sEVERE]    at java.lang.Class.forName0(Native Method)

23:28:18 [sEVERE]    at java.lang.Class.forName(Unknown Source)

23:28:18 [sEVERE]    at cpw.mods.fml.common.Loader.loadModClass(Loader.java:4

40)

23:28:18 [sEVERE]    at cpw.mods.fml.common.Loader.attemptFileLoad(Loader.jav

a:497)

23:28:18 [sEVERE]    at cpw.mods.fml.common.Loader.load(Loader.java:375)

23:28:18 [sEVERE]    at cpw.mods.fml.common.Loader.loadMods(Loader.java:527)

23:28:18 [sEVERE]    at cpw.mods.fml.server.FMLBukkitHandler.onPreLoad(FMLBuk

kitHandler.java:113)

23:28:18 [sEVERE]    at net.minecraft.server.MinecraftServer.init(MinecraftSe

rver.java:118)

23:28:18 [sEVERE]    at net.minecraft.server.MinecraftServer.run(MinecraftSer

ver.java:426)

23:28:18 [sEVERE]    at net.minecraft.server.ThreadServerApplication.run(Sour

ceFile:492)

23:28:18 [sEVERE] Unexpected exception

java.lang.UnsupportedClassVersionError: net/minecraft/server/mod_NetherOres : Un

supported major.minor version 51.0

    at java.lang.ClassLoader.defineClass1(Native Method)

    at java.lang.ClassLoader.defineClassCond(Unknown Source)

    at java.lang.ClassLoader.defineClass(Unknown Source)

    at java.security.SecureClassLoader.defineClass(Unknown Source)

    at java.net.URLClassLoader.defineClass(Unknown Source)

    at java.net.URLClassLoader.access$000(Unknown Source)

    at java.net.URLClassLoader$1.run(Unknown Source)

    at java.security.AccessController.doPrivileged(Native Method)

    at java.net.URLClassLoader.findClass(Unknown Source)

    at java.lang.ClassLoader.loadClass(Unknown Source)

    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)

    at java.lang.ClassLoader.loadClass(Unknown Source)

    at java.lang.ClassLoader.loadClass(Unknown Source)

    at java.lang.Class.forName0(Native Method)

    at java.lang.Class.forName(Unknown Source)

    at cpw.mods.fml.common.Loader.loadModClass(Loader.java:440)

    at cpw.mods.fml.common.Loader.attemptFileLoad(Loader.java:497)

    at cpw.mods.fml.common.Loader.load(Loader.java:375)

    at cpw.mods.fml.common.Loader.loadMods(Loader.java:527)

    at cpw.mods.fml.server.FMLBukkitHandler.onPreLoad(FMLBukkitHandler.java:

113)

    at net.minecraft.server.MinecraftServer.init(MinecraftServer.java:118)

    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:426)

    at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)

>

Link to pastebin of log:

http://pastebin.com/ThvmHRAX

[CreateNPlay]

Yeah i had this, update to Java 7