[unicorn]

Because you are trying to perform this mega format procedure from within XP and XP has a limit set for it there at 32 GB.
You can format all the 80 gigs using windows 98SE or WinME or Partition Magic or... However, why should you want 80 gigs formatted FAT32? Ok, I know, you don't ask for opinions, but I can't resist asking anyway.

EDIT: James; also read this:

Code:

http://support.microsoft.com/default.aspx?scid=kb;EN-US;q314463

for some info in general about FAT32 partitions and XP.