Hi there,
So the real error is "serial error".
Are you sure this is related to the communication between PC and Setter ?
I think I have seen this being caused by a low voltage on the interface PCB that sits in the filmsetter.
The Power supply going to this board should be a little bit above 5 Votls, because there is a voltage regulator on board.
We have seen all kind of "weird" things when this was set to 5 Volt or lower.
So I would check this voltage first ,and set it to 5.3 Volts,