Handlers error, help key up and down. Help Please!

I know that its pretty annoying to say that this problem was my problem for the entire week.
I just don’t understand how to fix this problem. I surf the net but I get no answer.

Situation :

Creating a game in flash cs5.5 as3. side scroll. just like beat em up games.

problems :

whenever I try to attack, it doesn’t stops. though I set the key up with false.

when i attack and move my character it moves left (left arrow) right(right arrow)

hope you could help me fix this problem thanks in advance.

-raphaelle-