The document could not be saved

When I open a online PDF file, I click the disk icon to
save the file, I got the message "

The document could not be saved, the disk were saving to
or the disk used for

temporary files is full. Free some space on this disk and
try again, or save to a different

disk"
1. The hard disk have 39 GB left.
2. I can save online other type files such as DOC files to
the same folder
3. I can save same online PDF file to other folders in the
same drive.
4. I can save both PDF and DOC files to this folder from
File Explorer, not from website.
5. To check this folder's properties, there is no
difference found from other folders.

I have tried IE and Netscape, both got same problem. So I
think it is XP system

problem.

Is there anyone can help me
Many thanks.
zhou