Is it possible, using actionscript 3 to disable the right click menu?
Any help greatly appreciated!
You can hide everything except for the Settings item, as said by Lain.
By the way: If you need to customize it you can use the ContextMenu class from the flash.ui package. Call hideBuiltInItems on it first to hide everything except for the Settings and then assign it to the menu property of the object you want to use the menu for (or root for the entire applet).
FYI, there is a nice tutorial about it that you can find here