Hey guys made my first test coaster cam vid today to share on my facebook page but I got one problem. Doseint seem to have audio to it. Has anyone got any idea how I can fix this for future videos?

The ingame video recording doesn't record the audio. That is why most people add music over their RCT3 videos with a video editor.

If you want the actual game audio with the video you have to use a video screen capture program like Fraps or similar.