I have several jobs, (differential and Transaction Log backups) that show up in the "In porgress" tab as still processing, however there is no change in any of the statistics when I run master..sqbstatus 1 and they are lised as complete in the "Activity History" tab. There is plenty of space available on the drives the backups are taking place on as well as the drives that they are being copied to.
I noticed in the documentation that I can supply mutliple "COPYTO" locations even though this option is not available in the GUI. Could copying to multiple locations be a source of the problem? It appears that the backups are correctly being copied.