Debugging issues with bb-histlog.sh on 4.3.0

I've some "random" failures on bb-histlog.sh, viewing items in the bb2 event log. Some work as expected, but some when clicked appear to do nothing. Hitting the URL for that (say http://den2sch17/hobbit-cgi/bb-histlog.sh?HOST=den1ws063&SERVICE=nfs&TIMEBUF...) with curl shows a zero-length reply. Checking the Apache error log shows "Premature end of script headers: bb-histlog.sh, referer: http://den2sch17/hobbit/bb2.html". I have found no core files left behind.

How is the best way to debug this problem, with no core files? Is there a good method to run this (or I suppose more specifically, hobbitsvc.cgi) under the debugger and feed it the request so I can tell why it is silently failing?

Thanks in advance for any suggestions. -Alan