Multiple Button movieclip control

Hi guys,
So I'm getting back into flash after 13 years out - attached is my .fla file. There are 3 buttons in there - ive got 2 working with
script but as soon as i add the 3rd button the script doesn't work. So basically is there anyone out there who can open this file
and put me out of my misery please... this is what I'm trying to script -

When a button is pressed tell the other button MC to finish its animation and play the new buttons MC.

Im still thinking in Actionscript 1/2 and ASC3 is all new to me,

thanks guys

Matt