hi,
Check the tomcat logs, especially the 'stderr.log' file which should show you the cause of the crash in most of the cases.
to make sure to get the precise information, I'd recommend deleting all the file in the tomcat logs directory and then start tomcat. after the tomcat server goes into stopped state check the stderr log.
when a tomcat server initializes completely, you get a message in the log saying 'server startup in xxx ms'. check if you see this message which would tell us if tomcat is crashing during initialization or after it.
As Prasad has stated, the version should be 7.x and not 6.x, if you're using the default tomcat in 4.1 SP04.
-Nikhil Nair