Final Cut Express Chroma Keyer Not Working??

[mackid16]

I have final cut express and ive been watching videos on youtube on how to chroma key with my green screen videos and I follow everything but the video on the side of the chroma key opetions just doesnt do anything atall. I have the picture that I want to use right under my video and I just cant seem to get it to work. Can anyone help me? If so tell me what i am possible doing wrong or not clicking/checking off or give me a detailed explanation on how to do it properly if possible.

thanks,mackid16

 

[spinnerlys]

Can you post a screen shot with the effect applied, the timeline, and the effect editor with the chroma key?