Error importing audio files

Hi, 

I wonder if you can help me. I'm trying to import audio files into my Storyline project. I'm able to select the file, but when it tries to load I get the following error message: 

An error occurred while importing this file. 

<Filename> does not appear to be a supported audio format.

I've not been able to import any audio files (either mp3 or wav) as I recieve this message each time. The audio files and the project are hosted on a local drive.

Does anyone know what's going on here?