Here's one possible solution (it worked for me): Found out by trial and error that XP didn't like DMA transfer mode for my Plextor 12/10/32 - burns stopped part way through the process. XP had set the transfer mode on my drive to DMA by default, even though the drive doesn't support it (according to Plextor, the drive is PIO Mode 4). I set the transfer mode on the drive to PIO, and all burning problems ceased without any noticeable loss in drive performance.
To change the transfer mode, go into Device Manager, select the IDE ATA/ATAPI Controller, select the channel the writer is on (primary or secondary), select the drive number of your writer (0 or 1), then change transfer mode to PIO Only. reboot, and that should solve your problem.