J.N.,
Right click on the GSP Tray icon from the System Tray and select System Identification String. Copy and then paste to a reply on this thread the entire contents from the Options section of the Gerber System ID dialog box. Having this information will assist in pointed and relative feedback to help troubleshoot your ArtPath issue.
My experience has shown that “a” device does need to be designated for ArtPath. Device doesn’t have to be real, doesn’t have to be “Gerber”, and it certainly doesn’t need to be physically connected. During setup there is no communication test to the port designated to “verify” the device.
More later once you have pasted your Options contents.