Universal Applescript Application

Is there a way to create Applescript as a launch-only application that will work on 10.5 and higher?

I'm running a lion. Whenever I save my script as an application to run, it does not work with 10.5 and gives me the error "does not work with this architecture."

The strange thing is that I once saved it and successfully ran it on machine 10.5, but when I went to edit it and save it again, it no longer worked.

thank