The path to the link may be too long - try putting mp3 and pres in one folder
and reinsert. Alternatively have a read here re. how to embed the file: http://www.technologytrish.co.uk/pptembedmp3.html
Two possibilities, the path to the media file is too long (place the file
and the presentation in a folder with a shorter path) or the media contains
DRM which PPT will not use.
