The configuration file contains an element that is not valid. The ReportServerUrl element is not a configuration file element.
I was configuring SSRS 2005 on Windows Server 2008, and on the last stretch (after several errors because of permissions on Windows Server 2008 side) .. I was getting this issue. It seems SSRS does not bode well if the server has more than one website.
What I had to do was to go to the RSWebApplication.config and comment out
       <ReportServerUrl>http:/MyDomain/ReportServer</ReportServerUrl>
        <!-- <ReportServerVirtualDirectory></ReportServerVirtualDirectory> -->
        <ReportBuilderTrustLevel>FullTrust</ReportBuilderTrustLevel>


 
		  
 
 
 
   
   
  
   
   
 
  
Great help!! I been look around in all config files on server since 2 hours and here it comes to end.. thanks