I had a similar problem last April on a 7.2 or 7.3 server (I can't remember exactly) that had not been updated. When clamav went into not supported it filled /var/temp with directories with the name of clamav<16 digit hex number> and each directory had the same copy of the signature files and this continued until the disk was full. I tried deleting the directories but they all came back within 30 minutes, after finding out clamav was unsupported I temporarily disabled it and deleted the directories to get my space back and the server back running. I then did an in-place upgrade to the latest SME and then applied all the patches and the problem was gone.
Yes, I learned my lesson, my server is now always patched up to date.
Hope this helps.
Lloyd.