HOWTO Get ASP.NET/C# work with Virtual Server...

HOWTO Get ASP.NET/C# work with Virtual Server...
Please help,
When I try to use the Virtual Server interfaces to get a list of Virtual Machines, I get the following error:
{Either a required impersonation level was not provided, or the provided impersonation level is invalid. (Exception from HRESULT: 0x80070542)}
        VMVirtualServerClass_This = new Microsoft.VirtualServer.Interop.VMVirtualServerClass();
        foreach
        (
          Microsoft.VirtualServer.Interop.IVMVirtualMachine IVMVirtualMachine_Temp
          in
          VMVirtualServerClass_This.VirtualMachines  // Throw the error here...
        )
The following attempt ...