The following fix, which I found by doing a "side-search" on the forum on the key word ADVRTMS.DAT fixed the problem.
http://forums.veritas.com/discussions/thread.jspa?forumID=103&threadID=48266&messageID=4369922긂
3. Please check whether the file ADVRTMS.DAT is present in the SYS volume in BKUPEXEC folder if not then please do the following:
1. do a bestop
2. create above file
3. enter IP address of the media server
4. then do a bestart again
This solution was noted in other 10.0 forum postings. What was NOT explained was that you, the user, needed to CREATE this file yourself if it was not there. A typical user, reading other postings, is reluctant to create this file, thinking it should already be there with the installation.
Thanks, and have a great day! :)