Temp folders in Program Files\...\VirusDefs consuming disk space.

Hello. I have an issue with a multitude of folders such as <tmp7671.tmp>, and <20060117.018>,

in C:\Program Files\Common Files\Symantec Shared\VirusDefs, created when I boot up. These folders are sometimes empty of files, sometimes filled with 60 or 70 MB of files. Yesterday I booted in safe mode to delete 400 <???....?.tmp> folders, freeing 5.9GB of disk space on my 9 GB hard drive. There is probably another gig of space being taken by the dated folders containing many duplicate files, which I have not deleted because I'm not sure of their importance. As of now, I have again accumulated 14 fresh <???....?.tmp> folders using about 500 MB of space.

Should these folders be getting deleted automatically when no longer needed? If so, how can I correct the program's clean-up function to perform these tasks.

Also, can I safely delete the dated folders such as the 2006 one above?