Problems playing video from my Casio EX-Z750

So I've been trying to play video that I've taken with my Digital Camera on my MBP. I've downloaded VLC and the video will play, but there's no sound. I've gone to the Casio website and downloaded a codec for the camera. It told me to put it in the quicktime folder. Well I put it in my user/library/quicktime folder and then tried it in my systems/library/quicktime folder and nothing. I still only get audio when I play the video in QT.
Any suggestions or help is greatly appreciated.

I believe the movies are MPEG-4, so you could try the method suggested here:
http://digitalmedia.oreilly.com/2005/03/09/casio_p505.html

(Scroll down two sections to 'Coping with Casio's Movie Codec')

Well I've downloaded the program FFmpegX and I've finally been able to convert a couple so that they play in VLC. My second problem is that I want to use the converted files in imovie. Any suggestions or advice?

the link for ffmpegx is here...http://homepage.mac.com/major4/