iostress and whistler

When I run iostress (version from the august plugfest) on Whistler one of my
drives that contains iostress disappears. The main dialog box never comes
up. It ends up with a readme.txt file in the drive and it says it is a UDF
device.I reboot the system the drive returns to normal. Whistler is on my C
drive. The drive that disappears is the D drive. I also have a E (fat),
F(fat32), G(NTFS).

Ken