There should be no issue.The issue is not with Symantec is with Microsoft MSDE install. You would have the same error installing another application that uses MSDE.Backup the system state on your DC's if you worried about it or contact Microsoft and ...
You need to upgrade to Backup Exec 10.1/d with Backup Exec 10.1 SP1If the SQL server is a remote server you will need to re-push the agent.10.1 is a free upgrade.
Change the PDC emulator role on the server your installing to the local DC your on. After install move the role back.http://support.veritas.com/docs/253790