I posted:

Is there a Perl explanation for this, or do I just have to beat my computer with a stick?

Apparently I do need to beat my computer with a stick. I copied all the relevant files to my home computer and it works fine. So tomorrow I get to figure out what's wrong with my work computer, but now I know it's not the Perl that's wrong. Anyway, thank you to everyone who responded, I learned a lot of good Perl stuff as a result of this annoying computer glitch!