It is home edition 4.5.561 with 0503-1 virus database.

I tested virus database updating on the my own computer, with C:\Documents and Settings[i]username[/i]\Local settings\Temp open the same time. The temporary files appeared there. But then, this computer has the “standard” C: drive with windows also there.

I could try to assign the letter C to some secondary drive tomorrow on the other machine, to see if it “fixes” the problem.