Audio Clips Now Have No Audio

I had 28 minutes of video edited in Premiere Pro that was shot with Canon XH-A1 in HD (1440 x 1080) in 24p. I captured it into PP as MPEG2 24p and everything was fine. Client shot additional 2 minutes on Canon XL2 in Standard Definition (720 x 480) in 24p and wants me to make a 30 minute film.

I created a new Project in PP as 720 x 480 24p and captured the SD footage and everything was okay. I copied and pasted the clips from the HD Project to the new SD Project, set scale on those clips to 45% and everything looked okay. When I saved it and went to bed audio and video was fine. I open the Project today and there is no audio on the clips I copied from the HD Project. The clips are there but there is no audio on them. Where the audio was visible before, the lines are now blank. Also, I saved the SD Project every hour under a new filename and every one of them is the same. Audio clips are there but there is no audio.

Where did my audio go? The clips are there and the captured video still has the audio on it.

Using Premiere Pro CS3 on new Dual Core 3ghz in Vista with 4ghz ram.

BTW, the submission deadline is Friday, 5 days from now and I really don't have time to re-edit the entire film.

Thanks