Error installing Application Request Routing

I'm trying to install IIS Application Request Routing 2.5 - with WebPI 4.0 under Windows Server 2008R2.

Unfortunately no menu shows up in IIS Manager.

Instead I get the following error in Event Viewer:

The Initialize method for module "Microsoft.Web.Management.Arr.ArrModule, Microsoft.Web.Management.Arr.Client, Version=7.2.4.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" of type "ApplicationRequestRouting" threw an exception.

Exception:System.IO.FileNotFoundException: Could not load file or assembly 'Microsoft.Web.Management.WebFarmClient, Version=7.1.2.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified. File name: 'Microsoft.Web.Management.WebFarmClient, Version=7.1.2.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' at Microsoft.Web.Management.Arr.ArrModule.Initialize(IServiceProvider serviceProvider, ModuleInfo moduleInfo) at Microsoft.Web.Management.Client.Connection.Initialize(WebManagementInfo webManagementInfo)

Indeed the WebFarmClient DLL is in the GAC in Version 7.1.2.1. (automatically resolved by WebPI)

How can I fix this?

Solution

OK.. here's the solution. Since another Version of the WebFarmClient DLL is in the GAC I had the idea to redirecting them:

Open C:\windows\system32\inetsrv\config\administration.config, which is the config file for IIS MANAGER (not for IIS itself).

Add this section into it (after configsections):

<!-- ... -->
</configSections>
<runtime>
      <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
         <dependentAssembly>
            <assemblyIdentity name="Microsoft.Web.Management.WebFarmClient"
                              publicKeyToken="31bf3856ad364e35"
                              culture="neutral" />
            <bindingRedirect oldVersion="7.1.2.0"
                             newVersion="7.1.2.1"/>
         </dependentAssembly>
      </assemblyBinding>
</runtime>

Here we go!