How do you refer to an Excel macro, an application that interacts with an Excel spreadsheet?

I am working with an application that provides a scripting interface with AppleScript. I need to call this AppleScript script from within an Excel macro. The script should read information from the spreadsheet, feed it to the application, and update the spreadsheet based on the results. When I run AppleScript by itself, it works fine, but when called from a macro, the macro executes. Below is an example to illustrate the problem I am facing:

VBA macro:

Sub Test()
    OSA = "/usr/bin/osascript"
    SCRIPT = "/tmp/TestScript.scpt"
    MacScript ("do shell script " & Chr(34) & OSA & " " & SCRIPT & Chr(34))
End Sub

      

        
        
        
      

    

TestScript.scpt

tell application "Microsoft Excel"
    tell active sheet of active workbook
        set value of range "A4:C5" to {{"a", "b", "c"}, {"d", "e", "f"}}
    end tell
end tell

      

        
        
        
      

    

If I run this script by itself it works fine and updates the active sheet. But if I call it from a macro like above, I get a Runtime 5 error on the line calling the script from the macro.

Any idea how to do this?