Problem with onEnterFrame. Please help!

Hi,
I have a short movie. In frame 1 some MCs appears on the stage by onEnterFrame and increasing _alpha. In frame 50, I want to zoom on these MCs by AS. The problem is that the fading continues even I have a if condition not to do that. How can I tell the movie stop fading and begin to zoom in frame 50?

thanks

mx-guest2004