Using CB fills C drive full and backup fails

Attempting to use CB to backup to a DVD drive. 65 GB backup setup to span disks. When starting I had about 20 GB free space on C drive. After about the 3rd or 4th disk the backup fails because the hard drive is full. Suspect the program is not deleting temporary files.

c:\documents and settings\ my user name\local settings\application data\microsoft\cd burning\comodo\

Found multiple temporary files that were 4,567,104 kb in size. I suspect that these are not getting deleted as the program is spanning disks.

I ruined several DVD disks because this backup keeps failing.