This is not a "reason": A company file with a scheduled report should be open to one user only.

It is ridiculous that this feature was implemented to only work in single user mode. Companies with multiple users stay in multi-user mode the great majority of the time and the concept of scheduling an automated report would be a great time saver. If you can generate a report while in multi-user mode you ought to be able to schedule and send that (or at least save it someplace automatically and let other apps take over distribution).