Steve,
BE 12D has been a disaster install for us as well. I upgraded from 11D hoping that the numerous issues we were facing might have been addressed in BE 12D. Unfortunately, not much has changed apart from the slick GUI.
Uninstall BE 12D once again, delete the Backup Exec folder with in program files in explorer, uninstall the SQL server database (assuming that the database was installed along with BE12D) and then try reinstalling.
It helped resolve multiple problems for me. I am still having issues with DLO option and CPS. But the primary program seems to be working fine and completed the first full backup successfully!