Severe JavaExceptions? PLEASE HELP

00:05:29 [INFO] guitarmasterjar1 lost connection: disconnect.quitting
00:05:29 [SEVERE] java.net.SocketException: Socket closed
00:05:29 [SEVERE] at java.net.SocketOutputStream.socketWrite(Unknown Sourc
e)
00:05:29 [SEVERE] at java.net.SocketOutputStream.write(Unknown Source)
00:05:29 [SEVERE] at java.io.BufferedOutputStream.flushBuffer(Unknown Sour
ce)
00:05:29 [SEVERE] at java.io.BufferedOutputStream.flush(Unknown Source)
00:05:29 [SEVERE] at java.io.DataOutputStream.flush(Unknown Source)
00:05:29 [SEVERE] at net.minecraft.server.NetworkWriterThread.run(SourceFi
le:103)

can anyone help me solve this? PLEASE!!!