I think that was a bug in 5.8.0 that was fixed for 5.8.1. I will take a look later and try and find the reference at perl.org (I have to go now for an hour or so).

If memory serves me correctly, the error only occurs as the program terminates and cleans up the threads, and doesn't actually effect the runtime operation of the program. I seem to recall resorting to adding POSIX::_exit() at the end of the program to avoid the problem occuring.

I'll take another look later and try to confirm my memory.