I'm sorry to hear the download version wouldn't work for you either, Lexxy. There do seem to be YouTube playthroughs of Whispered World, though.
I don't know if what Geo suggested would help. Usually games supply what's needed along with the game, but maybe the K-Lite pack would work better than what was supplied with the game. If you try the K-Lite pack and it works, please let us know.
Geo didn't give a link, but there's a download here at FileHippohttp://www.filehippo.com/download_klite_codec_pack/