Parser Error Message: The type 'System.Web.Mvc.ViewPage' is ambiguous

fixed it thus:

<runtime>

    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">

      <dependentAssembly>

        <assemblyIdentity name="System.Web.Mvc" publicKeyToken="31bf3856ad364e35"/>

        <bindingRedirect oldVersion="2.0.0.0" newVersion="4.0.0.0"/>

      </dependentAssembly>

    </assemblyBinding>

  </runtime>

also, look here.