Audio out of sync on FCP 7 export of 1080 HD footage

I am trying to export a sequence out of FCP 7.0 and the audio keeps going out of sync. The sequence plays fine in FCP but when I export it - either as reference QT file or self-contained QT file - the audio goes out of sync, right from the beginning of the sequence. The footage was originally shot on a Kodak Zi8 camera, in the 1080p mode. I then converted it into a QT file in Compressor, with the Apple ProRes 422 HQ setting with the frame rate changed to 29.97 and audio pass-through. That file looks perfectly good in FCP and the audio is in sync through the entire 28 minutes of footage. And again, the sequence looks fine in FCP with clean synced audio. It is only when I export the sequence out that the audio immediately goes out of sync. Any suggestions?