Hello. I don't know if you have solved this dilemna yet, as I can see no date on the posting. But I have also had this exact same problem, but with other software. I believe it may be a common cause regardless of the software. I had this problem with Ulead Video Studio, only after I re-installed Windows and had to install all my software again. The problem was that the decoder for the particular format that the audio was in was missing. Apparantly I had it before the re-install because of some previously used software. Unfortunately I had no idea which one it came from. You can buy and download the audio decoders from Windows, but I just eventually found another program that was capable of handling that particular format of audio. You have to remember that even though the imported video is all one file it still needs different things for the audio and video part of the file. The problem is that you need to know exactly which decoder you need.

This may not be the answer to your problem, but I figured I post it since it sounded so much like what I went through. And I remember how frustrating it was, especially when you have video waiting to be editted.