RE: Error - The value "" can't be evaluated into type Boolean.
Sorry...just realized you are in NAV--not BC.
For NAV, you CAN debug a Job Queue Entry, it's just a little trickier. Easiest thing to do would be to have your developer debug his own user session, and then run the desired object (codeunit or report) from the development environment.
If you must debug the Job Queue when it runs at the system-scheduled time, then it's best to put a delay in the Job Queue like this...
locaprocedure OnBeforeRunJobQueueEntry(var JobQueueEntry: Record "Job Queue Entry"; var Skip: Boolean)
begin
Sleep(10000); //to allow Session to show and be debugged
end
Then when the Job Queue is about to start, you refresh your "User Sessions" window repeatedly until you see the new session popup. Click debug, and you're off.