Error: RPC Requires Authentication 

An RPC security policy has been enabled, which is blocking DCOM communications needed for remote debugging.

To correct this error

1. Run \windir\system32\regedt32.exe

2. Locate and delete HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows NT\RPC\RestrictRemoteClients.

3. Restart your machine so the registry change will take effect.

4. If the problem persists, contact your domain administrator about the "Computer Configuration->Administrative Templates->System->Remote Procedure Call->Restrictions for Unauthenticated RPC clients" group policy setting.