The code in my script has regular double quotes. The particular line in my post above that you reference is copied directly from the website using clipboard, hence why the quotes are a little different, but that is not the case on the actual code in the script.
As said, the script works fine outside of ThinApp; a simple syntax error as the incorrect double quote character would make it fail outside of ThinApp (invalid character error), but that is not the case.
It appears to be ThinApp that is causing the issue in some way.