Michi,
Have you tried this:
appPED= CreateObject("MGCPCBLibraries.PartsEditorDlg" & "." & prog_id)
where prog_id is the COM Version.
I have done this and it works. I have to start my IDE with mglaunch, but it does run PDBEditor (in debug mode from the IDE) and executes functions normally. Same for the executable - start with mglaunch and it works as expected.
We do not have a Parts Manager license so I'm pretty sure that is not the issue. Per my Mentor AE, the Parts Manager license should not be required for any automation tools.