Actually, as it turns out, P3_2 *is* defined in the 8252 include file. I had performed the include statement improperly. So, there you go :)

Sorry to have initiated an argument, it was not my intention; Teaching yourself this sort of thing gets rather difficult at times... and I had just run out of ideas. Thanks to everyone - including Mr. Neil, whose information would definitely have helped in most cases (it didn't happen to apply to my problem, but it certainly could have) - for their assistance. Perhaps one day I can actually do some of this sort of thing professionally, and can afford a nice compiler like Keil :)