Digital BW, The Print

Hi folks, very much hoping you can help me out - I'm stumped.
I have a 1.8Ghz AMD Athlon running XP with PS6, have 1GB RAM, an 80GB 
hard disk partioned into three with 20GB dedicated as a scratch.

I am working with some pretty huge panorama pictures (up to 350MB), 
but also the run of the mill 100MB RGB files.

I am frequently getting a "disk error 36 (or disk error 1), problem 
writing to scratch disk, program must terminate".  Then it bombs out 
after another couple of "could not complete..." messages.

I can't seem to fix it.  I have my scratch set properly, am running 6 
cache levels with 90% RAM dedicated to PS.  I have run a defrag (they 
were truely fragmented!) but it doesn't seem to have helped.

Problem doesn't seem linked to any particular operation, but does 
occur most often when I try to print a large file.

Any ideas.....please.....

Steve.