try reinstalling your audio drivers. uninstall it, restart, reinstall it, restart. i know xp sp3 has a problem with hi-def audio exporting, but that shouldn't be an issue that'd cause this. this likely won't fix it, but it's worth a shot.
of course, if some program you installed at some point installed a driver for 32-bit audio (i doubt you're having an issue with 16 or 24 floating...and do these drivers even exist? i was under the impression that it's a hardware thing, not a software thing), and then when you reloaded windows you didn't reinstall that driver, that'd explain it.
can you import the files in audacity? if so, just re-encode them as whatever wave your computer can handle. or, try converting them with something like audiomove.
note that i didn't know anything about different formats of wave files, and i got everything in this post from this webpage. the second and third responses, actually. i know you're a busy guy, man, but you've gotta remember to do your own research before asking other people, particularly on a forum where most of the people are high schoolers that don't know much beyond FL's presets. i know it's easier, but you've been around a while and should probably know better =) you're still awesome, man.
now, since i'm really shooting from the hip, there's a good chance i'm wrong about what i've told you, so make sure you don't delete your source until you're sure it works =)