Scene problem

Hi, I’m using flash MX, and i’m having trouble with scenes.
I’m creating a movie that consists of 2 scenes, each with 1 movie clips.
when i test the movie, the two scenes play at the same time.
for your information, in the scene 1 i use 2 layers. the movie clip is in the second layer. the movie plays about 240 frames (in the ‘edit movie clip’ stage, in the scene stage, the playhead’s still in frame 1). then in scene 2 i use 2 layers also, the movie clip is in the second layer, the movie plays about 20 frames.
when i test the movie, the sound of scene 1 plays, the graphic won’t play, and the graphic in the scene 2 plays partly (not full).
Anybody have any idea what went wrong?
Sorry if my english is strange, i don’t usually use english in my country.
thanks in advance