XML or not to XML

hey there fellas -
I have a simple website going with four buttons. When a user hits on a button, I have a backround image fading in. User hits on another, button, that image fades out and i want another image to fade in.
The actionscript i am using is not bulletproof. Works sometimes, but if a user hits on buttons quickly, sometimes one image will not fade out and another will fade in giving me overlapping images. Not cool!
Is this something I should use XML to make the concept bulletproof. Please any advice to make this work properly 100% of the time.
Thanks!