Hi Paul,
I posted a sample script on our
Samples page
that shows how to cycle through a set of weather files stored in a folder. See instructions for running it in the comments at the top of the script.
It uses both simulate() and parsim(), and should help you sort out what might be wrong with your script. I tested it with SAM's default physical trough case, and the parallel simulations with parsim() generate the same results as sequential simulations with simulate().
If you use the weather files I posted in the .zip file for your tests, remove the "XXX broken weather file.csv" from the weather folder so that you can see the parout() output.
Best regards,
Paul.