update: ignore this first idea - I wasn't paying attention to you having to hit ^C...

Is it possible that it doesn't do anything because all the modules Bugzilla needs are already installed?

Perl scripts are usually interpreted by the perl program. If one is running, the ps command can list it. You can try:

ps -ef | grep perl
[download]

If that doesn't show anything other than 'grep perl', then you don't have any hung perl processes.

update: maybe checksetup.pl --verbose would help?