DLL version both exists in GAC

I have created an application and used reportviewer control(rdlc).
When i build the sln the error in application. The both version exists in GAC
Error The type 'Microsoft.Reporting.WebForms.ReportParameter' exists in both 'c:\Windows\assembly\GAC_MSIL\Microsoft.ReportViewer.WebForms\11.0.0.0__89845dcd8080cc91\Microsoft.ReportViewer.WebForms.DLL' and 'c:\Windows\assembly\GAC_MSIL\Microsoft.ReportViewer.WebForms\8.0.0.0__b03f5f7f11d50a3a\Microsoft.ReportViewer.WebForms.dll'
In web.config added the following lines
 <dependentAssembly>         <assemblyIdentity name="Microsoft.ReportViewer.WebForms" publicKeyToken="89845dcd8080cc91"/>         <codeBase version="11.0.0.0" href="Microsoft.ReportViewer.WebForms.dll"/>         <bindingRedirect oldVersion="8.0.0.0-10.0.0 ...