Correct me if I'm wrong, but isn't the solution PunkDark and Tango3D are discussing for the "There´s a problem with the disc you´re using. It may be dirty or damaged" error message? In my case there's no error message, it just continues to stay on the loading screen flashing "now loading" indefinitely.
Edit: Never mind, did a few more re-installs of the K-Lite Codec Pack and LAV Filters as described above, and despite not working before and being a slightly different issue, it seems to work now. Thanks again for all the help.