I don't understand it at all, but it seems like that was the problem. bjmsys is my own routine, it's just a wrapper around system(), where it prints the argument to the screen before calling system() if $v > 0. If I replace bjmsys with system in the top level code things seem to run fine.

As I said, I don't get it at all, but I just wanted the stupid thing to work and I guess I have my quick and dirty fix, so thanks!