Thank you for all the tips. I will try to come up with a short example code. In the meantime I can answer some of your questions.

I have not tried printing something, so this simple check is on top of my list. The backticks are not inside any sort of loop structure. I am sure, but I will double check this matter. I have not run it from the command line, but I did have sucess running it inside of a system call. The only issue was the output form the system call was not captured, and so this caused other errors.

Oh, thanks for the debug checklist, I've definitely got #1, now to start knocking away at the rest.