I wonder, is it possible that a portion of the script exists in a seperate file, and you failed to upload that file? It almost sounds like there's a file that you "do" into your script, which contains several subroutine definitions. I'm surprised that, if this hypothetical file doesn't exist on the new server, you're not getting an error message relating to the do command, but in that regard it's also possible that the do is held within an eval to trap errors.

You're also not using strict, are you?