Lori713 - You need to rewrite the system. You could shoehorn the old system in with the new back-ends, but it would be very risky. This is compounded by the fact that you have no test-suite.

I'd rewrite it using Test-Driven Development methods. Write the test, have it fail, then write the code that makes that test pass. Lather, rinse, repeat. There are a number of nodes regarding TDD on Perlmonks and other venues. It makes things very simple for a newer developer because you're focusing on results, not methods. Also, if you ever want to change something, you have a test-suite that describes what this thing is supposed to do. :-)

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We are the carpenters and bricklayers of the Information Age.

The idea is a little like C++ templates, except not quite so brain-meltingly complicated. -- TheDamian, Exegesis 6

Please remember that I'm crufty and crochety. All opinions are purely mine and all code is untested, unless otherwise specified.