What version of FileMaker are you using? The script and file techniques you're using indicate pre-7. But the script steps say something much more recent.
You should stay away from Copy and Paste and use modern techniques, like Set Field and Set Variable. And I'd recommend having one file with several tables. If that's not possible, you can still access related files.
In fact, you could replace each of your scripts here with a simple Go To Related Record script step.