One thing that struck me. If your not allowed to bring in external source, then what are you going to do if someone here offers you a solution? Re-type it, line-by-line, swicthing screens as described below?

If that's the case, then I would strongly recommend you go look at XML::Parser::Lite and borrow a copy typists:)

It's a pure perl module, runs on regexes, that emulates the working style of the 'real' XML::Parser. It's less than 150 lines, 200 if you include the pod -- don't go omitting the author copyright will you?. Be warned! It contains some long and hairy regexes that will be easy to screw up whilst copying.

Personally, I would ask management if they'll accept a pure perl module from outside. It's hard to see how they would be able to justify rejecting a pure perl module. It is literally no different, no greater or lesser risk, than if you had typed it in from your head.