Game online doesn't load (but works) and requests WebPlayer download despite already installed

I have a finished game i want to be played on a website read from a drop box file. The files are all there in the drop box sharing folder and I copied the HTML code into a HTML box on the website. So far so good it recognises the code and you can see unity text (the title, "Unity Web Player | [Game name]" in the box. However in the centre of the screen where you would usually see a loading bar there is a button linked asking to download the web player that then goes to the unity web player download page, despite 100% being installed already as the game works on the browser when being opened from the computer straight from the drop box folder, Is there anyone who can help me convince the site I want to run it on that the web player is there and allows game play to commence? - Thanks Internet People