OEntityPlayerMP lockup

[liquidox]

Had this last night, server was unreachable after that.

2011-01-31 01:52:57 [SEVERE] Unexpected exception
java.lang.ClassCastException: [I cannot be cast to OEntityPlayerMP
at OPlayerInstance.a(SourceFile:93)
at OPlayerInstance.a(SourceFile:106)
at OPlayerManager.a(OPlayerManager.java:19)
at OServerConfigurationManager.b(OServerConfigurationManager.java:205)
at net.minecraft.server.MinecraftServer.h(SourceFile:298)
at net.minecraft.server.MinecraftServer.run(SourceFile:235)
at OThreadServerApplication.run(SourceFile:512)

[kallakukku]

This happened to me once, but that was me losing my internet connection,