I seemed to remember that @...SAYs get lost/confused if you change/reset the SET PRINTER... in a way I'm surprised it worked in FPD. Why do you need to do this?

Also BTW it's good programming practice to reverse the order of SETs etc. when restoring settings:

*The below should be the first two lines of test.txt
set PRINTER TO test.txt
set DEVICE TO printer
set print on
? 'this is test1.'
? 'this is the 2nd line from the first printing.'
*set DEVICE TO screen
*set PRINTER to
*set print off
* Better:
set print off
set DEVICE TO screen
set PRINTER to