"beginner" Menu problem

I have a little problem with my menu buttons.
I have created 4 buttons wich are lined up next to each other with little space between them. Each button moves up on rollOver and down on rollOut, but when I move my mouse quickly over the buttons (in a modern pace) then sometimes my buttons keep in the rollOver state while the mouse all ready has rolledOut? Any clues to solve this problem? Maybe actionscript (not my strongest side) with x,y, position from mousepointer ??

Any help is appreciated,