Check the system message guide
http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/sw_6_3/msg__gd/emsg.htm
Are you seeing something similar to the following?
01. 9/25/2002,12:28:07: InbandPingProcessFailure:Module 1 not responding over inband
02. 9/25/2002,12:28:32: ProcessStatusPing:Module 1 not responding over SCP
03. 9/25/2002,12:28:32: ProcessStatusPing:Module 1 not responding... resetting module
Did you have any STP loops/High CPU at the time of the crash? The above messages are printed when the Supervisor's CPU gets pegged high. There was a bug file for this kind of crash saying the switch should not crash under these circumstances and is fixed now.
http://www.cisco.com/cgi-bin/bugtool/onebug.pl?bugid=CSCdx10436
6.3(9) should be a good software to run