I had been working with Symantec on the same problem. I have just decided to turn off source side deduplication and the duplicate to tape jobs run fine. For me, whenever I had "allow this job to have direct access to this device", I had random failures with catalog errors. Sometimes it worked, sometimes not. I think there is a bug somewhere. For me, it wasn't a huge deal as the source side deduplication wasn't saving me any time on my backup windows. The deduplication now occurs just on the media server. Hope this kind of helps.
Deryck