I'd run wireshark and compare the localhost cases with this script vs. with a "proper httpd". I suspect the proper httpd may send a very few relatively large packets while your Perl script may send a lot of tiny packets.

This seems likely to be a bug in your network driver. I have no guesses what precisely about the (presumed, possible) tiny packets (or just different packets) would make your driver so unhappy.

You might want to have another computer run a promiscuous wireshark / tcpdump so you can see the packets coming in and that make it out in the bluescreen case as well.