Flv playback speed

I have .mov file that was created @ 25fps by the client (can’t change this), when converted to .flv and played within my flash movie (which is @ 30fps (also can’t be changed)) the video speeds up and finishes about 3/4 seconds sooner, however the audio for the video plays at the right speed and finishes at the right time.

Can anyone explain why this is and/or offer any form of solution?