Using Veritas Backup Exec to backup multiple Win2003 servers I found a backup job hung indefinitely. You can request to cancel the job but that job also hangs. After stopping the Backup Exec Server, you may be able to eject the drive manually or may require restarting the Device & Media service as well.
The failed backup report logs stop after connecting to a BizTalk server.
Examining the Application Event log there shows:
Source COM+, Category (98), Event ID: 4689
The run-time environment has detected an inconsistency in its internal state. This indicates a potential instability in the process that could be caused by the custom components running in the COM+ application, the components they make use of, or other factors. Failed to add Subscription due to Store error.
The Help and support link supplies no information but links to http://support.microsoft.com/kb/909444/en-us where a description of Security Bulletin MS05-051 indicates changes in the COM+ catalog security settings.
Following the non-DC instructions reveals the security settings are indeed more aggressive than in the past. Making the appropriate changes allows a test backup of the BizTalk server to complete successfully.