As RahulG has said above that SBS comes bundled with DLO, here is another Steps that you may take. Firstly I must say that you getting that error because DLO was not properly installed. I may get the point that you don't want it but remember it is bundled.
The Steps:
1. Open Backup Exec Console.
2. Select Tools -> Install Options and License Keys on Media Server...
3. Select your installed SBS keys and Remove (Make a note before you remove it)
4. Then uncheck DLO option and now you will be working on a trial version.
5. Continue with the install and finish it, now you can test maintenance it should complete successfully.
6. Re-Install the keys and note they will install back the DLO Option keep on clicking next until finish.
7. If request for reboot do so, but it is not that critical. DLO should get installed fine.
8. Check C:\Program Files\Symantec\Backup\Data folder DLO should be there and check System Services as well.
9. You can go check the Maintenance or Dump DB from Utility tool it should complete successfully.
- Well having DLO even if you don't want to use its not nice but nothing will be broken as well
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My 2 Cents,
SamuelKN