how to solve error "Server does not support debugging of ASP.NET or ATL server applications" ?

hi all

First i installed all VS2008 components ,then i copied web application
which was configured to other machine IIS .But NO IIS in my system.So
later i installed IIS 5.1 in my system,then Opened that Web App and
try to configure virtual directory manually and debugged that solution in my system .But
it shows "Server does not support debugging of ASP.NET or ATL server applications" .So i tried solutions from microsoft web site to
register (C:\Windows Directory\Microsoft.Net\Framework\<Version>\aspnet_isapi.dll ) ,but still my problem dint get solved and could not debug that website.

What should i do now ?

Thanks in advance

S.Naveen...