Cannot install webplayer

Unity Engine
1

I use http://webplayer.unity3d.com/download_webplayer-3.x/3.0/uo/UnityObject.js to call the unity object

from some user who webplayer is not installed, error occurs when they click to install webplayer

unity webplayer install link : http://webplayer.unity3d.com/download_webplayer-3.x/3.0/co/UnityWebPlayer.application?installer=http%3A%2F%2Fwebplayer.unity3d.com%2Fdownload_webplayer-3.x%2FUnityWebPlayer.exe

Why does the error occurs?
What is it wrong?

2

Once you’ve downloaded it, close your browser, open the Task List and make sure InternetExplorer isn’t running in another process and then try installing the Web Player.