I have no idea what the chances are that you'll find someone who's had exactly the same problem and knows the answer off the top of their head. If we can't reproduce the problem, we can only guess what the problem is. You named "faq.pl" and "editfaq.pl" as the source of the problem. Both of those scripts include the files "thpl.pl" and "webtools.pl", each of those are over a thousand lines in length. I doubt most people will have the time to wade through those files. So your best bet to reach a wider audience is to give us something short with which we can reproduce your problem.

How would you debug this if you were in a remote location with no Internet to ask? You'd first isolate the problem by narrowing down the source of the issue. Cut away pieces of code, if the problem goes away, you know you just removed something essential to the problem, if not, keep cutting. Insert debug statements, see how far the code runs, and so on. See http://sscce.org/ and the Basic debugging checklist.