Cs2 liquify filter error "not enough space on the disc"

I have cs2 on my HP laptop
xp pro operating system
100 mg hard drive 25 mg free
2 gig of ram
exteral with 200 gig free
scratch disk set to first the c drive then to the external

when I try to do some liquifing, it works for a couple things and then in liquify mode says "not enough room on the drive"

What's going on?

Set scratch to the external only, your main drive is way too full. Do you really only have 25Mb of free space? If you do I'm surprised you can do anything at all.

that should have been 25 GIG free and 100 gig total c drive.....

Switched to the aux drive with over 200 gig free and still getting this same error