I've seen a lot of comments about the 5.2 versions of php not correctly recognizing the MP3 file type where 5.3+ will.  The obvious solution is to upgrade to 5.3, but sites such as mine using shared hosting are forced to wait until the host schedules the upgrade for all shared sites.  If you are in this category and are trying to get the zaudio, veeplay or other plugins to work, then simply override the "upload.php" under mod/file/actions/file.  Add the following just before the call to "SetMimeType" at or about line 241.

        if ($info['extension']=="mp3") {
            $mime_type = "audio/mpeg";
        }
This will force the type to mpeg on any upload with a .mp3 extension.

...  I thought this might help the community as it took me a while to find a decent workaround myself...