report viewer control in ssrs has disabled controls in webform

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C#

C#4.0

Hi,
I have search all over the internet but can not find the solution to my issue below:
I have deployed the asp.net webproject to the server.
There is a reportviewer which is supposed to show ssrs reports...
When I browse to it, it seems this report viewer is disabled. For example, there are drop down controls, and other controls which the user can not select (i.e. disabled).
Only the view report button is enabled and clicking on that makes no difference.
However, when I check the "view source" of the report viewer control, I see that there is data populated inside drop down controls in the report viewer.

The only question is WHY the controls in the report viewer seem to be disabled?

Below messages are what I see in the "view source" of the report viewer

<noscript>
	 Your browser does not support scripts or has been configured not to allow scripts.
</noscript>
-------------------------------------
Report Viewer Configuration Error
		</h2><p>The Report Viewer Web Control HTTP Handler has not been registered in the application's web.config file.  Add <add verb="*" path="Reserved.ReportViewerWebControl.axd" type = "Microsoft.Reporting.WebForms.HttpHandler, Microsoft.ReportViewer.WebForms, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" /> to the system.web/httpHandlers section of the web.config file, or add <add name="ReportViewerWebControlHandler" preCondition="integratedMode" verb="*" path="Reserved.ReportViewerWebControl.axd" type="Microsoft.Reporting.WebForms.HttpHandler, Microsoft.ReportViewer.WebForms, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" /> to the system.webServer/handlers section for Internet Information Services 7 or later.</p>
-------------------------------------

NOTE that in the webconfing I do have the following :

<system.web>
    <httpHandlers>
      <add verb="*" path="Reserved.ReportViewerWebControl.axd" type="Microsoft.Reporting.WebForms.HttpHandler, Microsoft.ReportViewer.WebForms, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" validate="false"/>
    </httpHandlers>
...
...
...

<system.webServer>
    <modules runAllManagedModulesForAllRequests="true"/>
    <validation validateIntegratedModeConfiguration="false"/>
    <handlers>
      <add name="ReportViewerWebControlHandler" preCondition="integratedMode" verb="*" path="Reserved.ReportViewerWebControl.axd" type="Microsoft.Reporting.WebForms.HttpHandler, Microsoft.ReportViewer.WebForms, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"/>
    </handlers>
  </system.webServer>
...
...