While continuing the aforementioned porting process, I noticed a line in the INI config reader that I thought shouldn't work. But it had never blown up before so I figured I was wrong and went along my way.
A few minutes later I was creating some tests for these pieces when wouldn't you know, the test blew up right at that point. A ten-second fix later and a 'perl t/config_ini.t' I get all 'ok' lines back and feel a warm glow inside. (Notice how the warm fuzzies immediately override the cold pricklies that must have been there due to this bug being in the INI reader for, um, a while.)