You've received help with your actual problem. But, I will point out that the "No CPAN modules" restriction is a restriction only in your mind. The code is freely available - just cut'n'paste the subroutines you care about into your code. Attribute the original author if you have a conscience (and can do so in your shop) and move on. There have been several times where I've had to do that in my career.
My criteria for good software:
- Does it work?
- Can someone else come in, make a change, and be reasonably certain no bugs were introduced?