It Instaled ok for me but you have to run the view client install exe rather than install through the browser
The people having trouble have done it through the direct install of the .exe but I don't know the errors they received... will have to check out what the problems were.
I am running the View 4 client without any issues and honestly can't remember if I had windows 7 when ruing the 3.1 client. Another thing to look at would be UAC. Might have them try disabling that to install or at least downloading the exe and running as administrator.
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