Random assets missing.

A couple weeks back I did some voice over recording for a film using Audition. When I was finished I saved the file, and closed it until I would need them. Now when I try to open the .sesx file it says that 37 of the 42 files referenced could not be found. When I look in the source folder the files are there, but only 5 of the files can I actually open in audition or itunes. They are all .wav files, but only some of them will open. The others ask what program it should use to open them with. If you have any ideas of how to fix this I would be most grateful! Thank you for your time!

I have attached a few pictures to show what is happening. The first shows the source files. Track 1_037.wav is the only one in this picture I can open.

The second picture shows how only a few of the files are working in the program.