Audio out of sync and missing

I have several clips from my Panasonic LX-5 (720P). I created a new project (CS 5.5) and imported the clips. When I play the file directly from Windows Explorer, all is well. However, in the timeline, the audio is way ahead of the video and then part way through a clip, the audio disappears altogether. Also, the line at the top of the sequence is yellow (above transitions, it is green). I thought maybe the final exported file would be fine, but it had the audio out of sync and missing in the same spots, too.

Any ideas what's going on here?

Thanks,

Jay