Help me!Server problems

[Flinty]

I was trying to set up a small server for my friends and this error came up.I dont know whats causing it but i tried fixing the ram allocation and stuff.

C:\Users\Migs\Desktop\Hexxit Adventure!>java -Xmx3G -Xms2G -jar Hexxit.jar nogui

2013-06-22 21:17:17 [iNFO] [ForgeModLoader] Forge Mod Loader version missing.mis

sing.missing.missing for Minecraft missing loading

2013-06-22 21:17:17 [iNFO] [ForgeModLoader] Java is Java HotSpot 64-Bit Serv

er VM, version 1.7.0_21, running on Windows 7:amd64:6.1, installed at C:\Program

Files\Java\jre7

2013-06-22 21:17:17 [WARNING] [ForgeModLoader] The coremod bspkrs.treecapitator.

fml.asm.TreeCapitatorCorePlugin does not have a MCVersion annotation, it may cau

se issues with this version of Minecraft

2013-06-22 21:17:17 [iNFO] [sTDERR] Exception in thread "main" java.lang.Runtime

Exception: java.lang.NoClassDefFoundError: cpw/mods/fml/common/versioning/Artifa

ctVersion

2013-06-22 21:17:17 [iNFO] [sTDERR] at cpw.mods.fml.relauncher.FMLRelauncher

.setupHome(FMLRelauncher.java:192)

2013-06-22 21:17:17 [iNFO] [sTDERR] at cpw.mods.fml.relauncher.FMLRelauncher

.relaunchServer(FMLRelauncher.java:147)

2013-06-22 21:17:17 [iNFO] [sTDERR] at cpw.mods.fml.relauncher.FMLRelauncher

.handleServerRelaunch(FMLRelauncher.java:45)

2013-06-22 21:17:17 [iNFO] [sTDERR] at net.minecraft.server.MinecraftServer.

main(MinecraftServer.java:1367)

2013-06-22 21:17:17 [iNFO] [sTDERR] Caused by: java.lang.NoClassDefFoundError: c

pw/mods/fml/common/versioning/ArtifactVersion

2013-06-22 21:17:17 [iNFO] [sTDERR] at java.lang.Class.forName0(Native Metho

d)

C:\Users\Migs\Desktop\Hexxit Adventure!>pause

Press any key to continue . . .