as3 in timeline and class

Hi folks.

I'm trying my best in a game project, but just can't do it right.... I'm a complete noob in as3 (have done my share of simple as2 though, possibly that's my problem..), but have managed to get to a certain point in the project where I have game functionality, but now i stumble where I thought would be no problem at all. I made a game where all the "gaming" code is in the external .as file, and it all works fine, but when I add a code to the timeline from code snippets, it all stops working.

Is it possible that .as code and timeline code don't work together?

Thnx in advance