This happens when I join MY 1.4.2 server

[SEVERE] Encountered an unexpected exception ArrayIndexOutOfBoundsException
java.lang.ArrayIndexOutOfBoundsException: 4
at ln.bB(SourceFile:1739)
at pw.bB(SourceFile:199)
at pw.bD(SourceFile:222)
at xr.a(SourceFile:162)
at xr.a(SourceFile:139)
at ie.b(SourceFile:106)
at net.minecraft.server.MinecraftServer.r(SourceFile:717)
at hg.r(SourceFile:233)
at net.minecraft.server.MinecraftServer.q(SourceFile:661)
at net.minecraft.server.MinecraftServer.run(SourceFile:595)
at fp.run(SourceFile:818)
[SEVERE] This crash report has been saved to: D:\Minecraft\Minecraft Server - Copy\.\crash-reports\crash-2012-11-14_14.29.16-server.txt