trouble printing to video.

I have a 40-minute film that I exported to an 8 GB Quick Time file. This QT file plays beautifully in my QT player, but when I import it into FCP the trouble begins. I put the 8 GB file in a new sequence and it seems to playback on my computer okay, but as soon as I try to record playback or print to video I get audio glitches. 25 minutes into the film the audio and video become obviously out of sink. Any help would be much appreciated.