Just attempted to upgrade one of the Small Business Server 2003 Premium servers from Symantec Client Security (SCS) or was that Symantec AntiVirus (SAV), well v10.2 anyway. Old version System Center Console (SCC) came off ok, rebooted and the new Symantec EndPoint Manager (SEPM) went on without error. However the newly packaged client for the server - AntiVirus and AntiSpyware modules only - wouldn't install. It got most of the way there and then suddenly rolled back without an error. There was a simple error event id 11708 from msiinstaller, operation failed.
Sounded just like some problems discussed on Experts Exchange and the Symantec forums. There was a whole thread dedicated to people opening support cases and requesting EndPoint Cleanwipe. So I did the same and within 20 minutes had a copy off Symantec ftp. It didn't fix the problem but wasted a couple of hours trashing the SEPM install as well as the previous Mail Security for Exchange. So after reinstalling both I was back to square one. Twelve hours later, Symantec tech support popped up having gotten around to reading the install log. Turns out there was an old Alert Management Server installed. It wouldn't remove from Add/Remote Programs or via CleanWipe.
The Microsoft Windows Installer Cleanup tool went all Chuck Norris on it and saved the day. One reboot later and a successful client install :-)