Finally got both 8.1 and 8.0c loaded. Appears that the permissions were incorrect in the Sony/Vegas 8.0 folder and sub folders. It was a long and difficult process to correct each file. Some of the sub folders were able to be corrected using inherit from parent folder but many I had to go in and manually reassign the ownership first and then reset the permissions to Full control second. Once this was done I was able to do the two upgrades.
A few of my plugins don’t seem to work with 8.1 but with 8.0c loaded I think I’ll have what I need.