Lauching Files issue

I've visited the tuturials for launching PDF and other files from a cd on a mac, i've made apple scripts and they work, but for some reason my projector will not launch them.

my button script is:

on (release) {
fscommand("exec", "CH21");

}

CH21 is the apple script name. does an extention have to be here too?
I saved the script as an application

Surely you'd need the absolute URI with the extension?

Not sure whether the path has to relative or absolute, but you'll definitely need the extension on it (select your AppleScript, do Apple I to Get Info if you want to find the extension).