Not sure if anyone else has run into this, but I've seen it on three separate windows installations on Win2k8 so far, in version 8+. It only seems to affect the jboss service.
Restarting the Interwoven JBoss Application Server via the services panel results in the service hanging on "Stopping". I haven't managed to find a fix, but here's a workaround:
Open a command prompt as administrator.
type in the following:
sc queryex iwjbossd
From the output, grab the PID, then:
taskkill /pid /f
You should now be able to start jboss normally from the services menu.