Why a button stops working

so i have some arrow buttons (actually movie clips being treated as buttons via actionscript).

All the states work fine, onRollOver, onRollout, onRelease.

But for some reason you can’t continually click the arrow to proceed to the next image unless you move the mouse at least 1 pixel before each click. I would like it to be able to be clicked repetitively without the user having to move the mouse little bit.

is there some bit of code that needs to go on the “onRelease” to reset the button or something?

Thank you::::::::-