Well done, and I certainly do think you are correct in that Perl threading is rather... dangerous. I have written several wrapper programs (mostly java and c) to avoid Perl threading at all costs. The performance hit isn't so bad and in the long run I wasn't using up anything more than a lot of memory really.

I've played around with Perl threading a little and found plenty of bizarre problems that I could attribute to Perl, my code or anything else so I just have to assume it is all in the nature of Perl threads not being terribly safe.