To better understand your issue, could you try the following steps:
1. Create a blank Simulink Model
2. Insert the "From MultiMedia File" block to your Simulink Model
3. Double click the " From MultiMedia File" block, in the file name area, use Browse to choose the audio file you want to import.
4. Click Apply, then click OK.
If you still get the same error, could you try some different audio files? For example, some sample audio files from the website. Make sure the file is on your MATLAB search path. For more information regarding supported platforms and file types of "From MultiMedia File", please refer to the following link: https://www.mathworks.com/help/dsp/ref/frommultimediafile.html