I forgot to mention that other PCMCIA cards work fine in the Toshiba, which suggests that there's actually some kind of software incompatibility going on, but the only non-standard software on the box at the moment is the Sprint drivers (which work fine on other laptops) and the Toshiba drivers (which are needed to operate the laptop), so it's possible that the laptop drivers themselves are incompatible with this card.

I suspect you guys are right, I'll just have to spend 1000 years on the phone with Toshiba and get a different model.

Ah well, so much for having a working system by tomorrow...