Unity Webplayer not working

I have Unity 4, Windows 7 x64 and Firefox & Chrome, I am trying to make a deployment on the webplayer of my current scene, the problem is when I enter the page (.html) the webplayer says

Error launching player

When I click on error details I get Failed To Load Unity DLL. I have installed and uninstalled the webplayer multiple times and haven’t found a solution.

Any ideas?

Are you able to view other web player apps? Like on the unity examples page?

http://unity3d.com/gallery/demos/live-demos#camper

Is this being run just off your desktop or through IIS or your website?