Dear Sir:
Providing that you cannot come up with a simpler or faster solution such reinstalling the NET Framework or any other faulting components of the program, and also if repairing doe not work, let me suggest to you this workaround:
(If you are using a Deduplication Folder or have implemented the CASO or SSO options, please do not do this).
You will need to have the installed CD or files for BE version 2010 R3.
1. Stop the Backup Exec services and make a copy of the Data and Catalogs directories located in the program folder at \program files\symantec\backup exec.
2. With Add Remove Programs on Windows remove the program COMPLETELY, including associated files.
3. After removingg the program, make sure that there are no files in the disk drive related to Backup Exec.
4. Reboot.
5. Install Backup Exec fresh. Use the same System Logon Account that was configured in the old installation.
6. Stop the Services, and rename the DATA folder to DATANEW and the CATALOGS folder to CATALOGSNEW.
7. Bring to the program folder the DATA and CATALOGS folders that you backed up in Step 1.
8. Start the services and BE should behave as when it was previously installed.
Regards,