Get (Buttons/) Layers inactive

Hi guys !

just started into FlashMX, and now i got a little problem.
I made a scene with 5 lockers, which you can open and close by clicking on them.
The thing is, is just want one locker to be able for opening at the same time.
Cause otherwise its all mixed up withe look it should have.
Is there a possibility to lock one layer, as a button on the other layer is active ??
I tried it with the “buttonX.enable=true” commands, but dindt work for me…

Heres a link where you can take a look at it, then you should know what i mean (-:
http://members.chello.at/sandberg/home.html

thanks for your help !