This wasn't my specific problem...but similar. I downloaded my first transcription .wav files and then Scribe wouldn't open them..."audio compression codec" problem, then crashed. I spent 4 days puzzling this one through. I couldn't even use Switch. The problem was that they were downloading as a .dct (or .dtc or whatever) file instead of .wav. Then I found the solution.
1) I updated my media player to version 10
2) I checked under "tools", "options" and ..hmmm I think it was the tab for file extensions or some such. The whole list of supported formats was checked EXCEPT .wav! Go figure. So when I checked the .wav box, closed, and downloaded the file again to my computer and it downloaded as a media player icon and loaded perfectly into my Scribe and played fine.
Maybe this will be helpful to others.
Blessings,
Puzzler