Nancy - A Flush operation refers to writing to tape all the data
        which the tape drive has buffered...a sync operation.
Sounds like you have a drive problem.  But I've experienced what
seem to be drive problems when the actual problem was a cable
or SCSI terminator.  (We had what looked like a drive problem
for about a year: switching the terminator caused the problem to
go away.  Lesson: never overlook trivial causes.)

   Richard Sims