The only thing that error message really tells you is that FileMaker, for some reason, was unable to create the PDF file on your computer. The most common cause of this error is an incorrect file path. I can't check that in your script as the filepath seems to come from a field of that name (It is extremely hard to read your script screen shot.)
Have you double checked the value of that field when you get this error message?
Maybe this is better.
But this still does not show the value of SOrders::TempPath and this is the field you need to check for a valid file path the next time you get this error.