>Always take care with messageboxes and wait windows when called from an event on a form or control. If you call them from for example an activate event in your form or pagetab, they retrigger the same event again when you return to the form and this might cause your problem.

Thanks for responding.

I don't think this is the problem, though, since I get the same results with oShell.Run(program) when program has no user interaction whatsoever.