Disapearing schedules

I am having a strange experience when adding a schedule to Integration Server. It will appear to save and work for a few days / weeks. Then for some reason, the schedule will disapear, even though other schedules remain intact. Any ideas?

Two questions:

  1. What is your IS environment like? One server or more? Using clustered scheduled services? Using reposerver?

  2. Do you ever have IS crash, or are you ever unable to shut IS down from the admin console? If this happens the jobs.cnf file will not be updated, and new entries added from the admin console will not be there when you start IS again.