What am I missing in this RemoteServerMethod call

   So in my LaorWare2011Web project I have a folder named RemoteCalls and in there is a class called MemberBalanceCalculator defined as follows:

namespace LaborWare2011Web.RemoteCalls
{
      public static class MemberBalanceCalculator
      {

             [AllowRpc]
             public static object CalculateAmountOwing(Member member)
            {
                     // a bunch of calculations.......

                     return member;
             }
      }
}

In my MemberEditViewModel class, I have a method that will call this remote method.

public void CalculateBalance()
{
      string typeName = "LaborWare2011Web.RemoteCalls.MemberBalanceCalculator, LaborWare2011Web";
      string methodName = "CalculateAmountOwing";
      var op = Mgr.InvokeServerMethodAsync(typeName, methodName, null, CurrentMember);
      op.Completed += (o, args) => {
      };
}