Does the location where you save the PDF make a difference? As a temporary test, what if you use Get ( DesktopPath ) instead of Get (TemporaryPath)?What if you use "file:" instead of "filemac:"?
Neither of these should make a difference, but if they do, they may provide a key clue in helping TS folks isolate the cause and may also identify work arounds.
Also, have you created a small brand new test file on your system and tried out this same script in it?
All of this, BTW, should be reported over in the Report an Issue (see tabs at top of this screen) section of the forum. You can include a link to this thread in your issue report if you want to save some typing.
You lead me to the right answer with your first statement of file vrs filemac. When I took a closer look at the dialog in the "Insert PDF" script set it is looking for a "image: or imagemac:" instead of "file: or filemac:"
I replaced my filemac: with imagemac: and it works fine now. I guess I wasn't observant enough until you guided me there.