I experienced this same problem installing the plugin on a webserver and that was due to the permission restriction.
Solving the problem is quite easy:
1. Locate the file via your FTP client;
2. select it and open the info box (I'm using Transmit where this action is available from the contextual menu on the file);
3. locate where the permission settings are (here is a screenshot of the Transmit info box: https://dl.dropbox.com/u/1976976/wp_components/mb.miniaudioplayer/before.jpg )
4. set all the "execute" permissions to true (here is the Trasmit screenshot: https://dl.dropbox.com/u/1976976/wp_components/mb.miniaudioplayer/after.jpg );
5. Now the page has all the permissions and the problem should be fixed.
If you can't do that via the FTP client you can download the plugin locally on your computer, check the permission there and eventually set them correctly and upload the plugin via FTP.
Unfortunately this is not a problem of coding and I can't overwrite the server settings on permissions and on most installations that doesn't happen; so this problem is fixable only by you.
I'll see if it is possible to pass those parameters somehow else and hope to find the way.
Hope this can help you,