One solution would be to set a CONNECT limit on the job.  If the job
takes longer than 3 hours (a normal backup time?) then abort the job.
Or, you could do some thing like this:
 
:BUILD TRUE
:TELLOP Backup will not procede until file TRUE is purged.
 Then set up a while loop to scan for the presence of the file.  When the
scan for file presence is false, then backup can commence.  Otherwise,
the program can keep scanning, or, after an interval of time, quit.  I'm
sorry I can't elaborate furthur, as it has been a while since I've used
MPE, I can't remember semantics of MPE scripting.  Hope this helps!
 
Dan Kosack [log in to unmask]