The first error has nothing to do with fork. It happends always and on every os (or atleast on the ones I tested)...

I guess it comes because the BEGIN-block is run at compile-time, and the compiling of the code failed. (you called die...)

perl -wle "BEGIN { die; }" produces exactly the same error.

I guess (I'm not sure of this at all!) that the second error occures because the parent died before the child was run... (! fork() means not undef, and not 0, if the parents executes fork() then it returns the pid of the child which is not 0).

This would then mean that the proces is dead, but that there are still threads alive, which should give problems (or not?)... (I could be wrong on this one, as I said, I'm guessing)

The fork emulation on Windows creates a new thread inside the proces, fork on unix/linux/... creates a new proces, which is slightly different I guess.

Update, as RazorbladeBidet I got it backward.. What was I thinking? :)