[Than Baardson] "I've linked and avi to the background of the menu and tried importing it as an AE comp"
How are you setting as the background? Are you Going to the motion tab of the menu and setting the video and audio asset to that of the avi or dynamic linked composition?
Also if your system is really slow or the avi is extremely large, it may not be able to update the motion background in the preview. Have you tried rendering motion menus and see if that works?
Jon Geddes
www.precomposed.com