I have 2 different filemaker pro apps running, named FMPRO5 and FMPRO6 under MacOS 9.2. A specific file, called Master.fp6, needs to be opened automatically under FMPRO6, but it always gets opened in FMPRO5. How can I force to do this, using Applescript ?

thanks for your help.

Try this (tested only under OS-X):

set f to alias "path:to:file:to:open"
tell application "Finder" to open f using alias "path:to:FMPRO6"