We have recently updated our own Backup Exec installation to 2010. The update process was to uninstall v10D and then install Backup Exec 2010 afresh. The same user credentials are being used for the backup jobs and all but the System State is being backed up successfully.
When backing up the System State the job always gets an error: "e00084af - The directory or file was not found, or could not be accessed."
All three possibilities in http://seer.entsupport.symantec.com/docs/326836.htm
have been ruled out. The System State obviously exists on the server & is not a "missing directory." The credentials in use are correct (they're being used for the rest of the backup & working) and the system state backup does not work if the user credentials are removed either. TCP Port 10,000 is definitely being listened to by beremote.exe (confirmed via "netstat -ano" and task manager with PID column).