vista beta2 would not install unless primary c drive ha

Tried installing Vista Beta 2 x64 in a dual-boot setup, where my C: drive (38GB) had windows xp installed, and then another 16.8GB partition where I was trying to install Vista. At first, whenever I tried to install, I would always get an error after selecting the partition to install too: "Setup was unable to locate a locally attached hard drive suitable for holding temporary Setup files."
At first this puzzled me; 16.8GB should be plenty to at least install Vista. Then I had the crazy idea that maybe setup was trying to copy the temporary files to my C: drive, which only had 3GB free. So I free'd up some space (around 5GB), started the install again, and sure enough setup continued just fine.
Might be a good idea to fix the installer so that it will copy temporary files to another drive, if the first drive does not have enough space. Or at the very least, it would help to inform the user of what drive the installer is attempting to use for temporary storage.
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