Things I would first check: That client and server are syncing to a time standard, for overall sanity. Check for any errors in dsmerror.log. On the server side, do 'Query SEssion F=D' and see what's going on with that node, and inspect the Activity Log for issues regarding the session. Backups are relatively low priority, so long waits for tape drives are possible. In Windows, look for any questionable Event Log entries, and see if the dsmc scheduler process is using any CPU, if the server indicates it healthy.
Richard Sims