This is just a preliminary response, I'll look into it more if this doesn't work. It looks like the problem is that your anonymous sub needs to exit at the end, not just return as yours is. The example in the book has the spawn subroutine called with an anonymous sub that execs at the end, and an exec exits at the end, never returning control to the program. Anyways, I haven't looked at the code for the spawn sub yet, but I'll do that and see if anything else that you might need to do stands out.