no sound on audio file(0 bytes) but the image .peak is there

I recently recorded a podcast with 4 mic inputs through my m-audio fast track ultra onto a usb drive. All looked fine while recording. The wave forms were showing on screen and my test tracks sounded fine. However when it came time to record something must have happened and now the files that are on cubase (5) show that there is audio but there is no sound. The .peak files are there and it looks as if there should be sound, but the audio files show 0 bytes and therefor have no sound. I am guessing the files had gotten corrupt or something along those lines. Is there any possible chance of recovering the audio files or i it a lost cause?