For anyone else spending an unfortunate length of time unsuccessfully attempting to capture keyboard events in a Flex 3 application (for browser or AIR), here’s where you’re probably going wrong.
You are likely registering the keyboard listener too early. It’s likely that you are calling an init() method where you register the keyboard event on creationComplete. Instead, call the init function later on. Try registering the event in the applicationComplete event handler.
More info here:
http://www.adobe.com/cfusion/communityengine/index.cfm?event=showdetails&productId=2&postId=304
