Hello Tony,
Thank you for selecting to use Symantec's online forums.
If neither Backup Exec nor NT Backup can backup the Information Store, then you should research this further Microsoft.
I did some intial research for you and found an article, 840013, which has some information based on the follow string:
call to 'HrESEBackupRead()'
Once you are able to perform an Information Store backup with NT Backup, then Backup Exec should also operate correctly.