I think that might be it, I tend to have the worst luck with everything =_= I'll give them a call on Friday when I'm not scrambling around to prepare for a presentation and a lecture I have to give to a class tomorrow (and then go to a 7 hour class afterward, yaaay college).

Yup, I tested the old one attached to the tank with an extension cord (that I KNOW works because I use it with my laptop) and an outlet in a completely different room without the thermostat, tested the spare (that I JUST opened) in another room without the thermostat, and left them sit for an hour. Nothing.

I have the new one now hooked up and running, plugged it into my bedroom outlets to test it and then into the thermostat. It's warming up now. :| I have no idea why the others failed, but when I get to work in a few days I'm buying one of those three-outlet surge protectors and throwing my set up on one of those instead. I'll also place the order for the heat packs just in case this happens again. Thunderstorm season started a few days ago so I might as well just in case.