To execute a plain text or compiled Applescript script (.scpt) in the method LAUNCH EXTERNAL PROCESS, make sure to call the OSASCRIPT command. An example:


LAUNCH EXTERNAL PROCESS("osascript /Applications/AppleScript/Example\ Scripts/Basics/AppleScript\ Website.scpt")


4D treats the execution of shells and apps as if they were executed from the Terminal, and the OSASCRIPT command is necessary to run an Applescript through the Terminal:

https://developer.apple.com/documentation/AppleScript/Conceptual/AppleScriptX/Concepts/work_with_as.html