I cant switch the version vrom 3 to 4.1 … when i click there is no 
release channel so i cant go from 3 to 4 help me plz
Have you tried reinstalling the plugin? By the looks of the screenshot you have an older plugin version. Get the latest from Unity Real-Time Development Platform | 3D, 2D, VR & AR Engine
What browser version and OS are you using? Can you paste the logfile from the plugin that is produced when you access the setup page?
See Unity - Manual: Log files on where to find those.