When you click a script and choose Open with [application] then the file gets downloaded to your temp directory with the .txt extension. The application then fails to load the file
C:\Users\xxxxx\AppData\Local\Temp\NameOfScript.funscript.txt C:\Users\xxxxx\AppData\Local\Temp\NameOfScript.funscript-1.txt C:\Users\xxxxx\AppData\Local\Temp\NameOfScript.funscript-2.txt
On RTS this is not an issue so it might be an only a problem with this website.
I could write a workaround for that but I thought there is maybe a setting to fix that.