PowerPoint won't open files from thumb drives

Version: 2008
Operating System: Mac OS X 10.5 (Leopard)
Processor: intel

PowerPoint 2008 absolutely refuses to open or read any files saved on a
FAT32 thumb drive. If I try to save a new file there, it simply saves it
in my home folder instead, and if I try to open a file, it complains that
the file is in the wrong format. The thumb drive works just fine, and
every other programme can open files just fine. Any fix for this? I really
need to be able to run presentations off a thumb drive.