Which version of jdk are you using?
The other way to get the stacktrace is to start the appserver
using asadmin start-domain --verbose so that appserver will start
printing output to a console. Wait until you see the problem.
When you see the problem, press ctrl+backslash and that will
print the thread dump to the console.
Also, when you say server is not responding, can you access the
admin GUI?
thanks,
Binod.