title: Index (zero based) must be greater than or equal to zero and less than the size of the argument list. error when adding domain service class
body: <p>I'am using a silverlight business project template to create a simple silverlight app for our company. In a different assembly i have created a data model using EF 4.2 with a code first approach. When i try to add a new domain service class i get an error message box with "Index (zero based) must be greater than or equal to zero and less than the size of the argument list.". </p>
  
  <p>I'am using RIA Services V1.0 SP2 and RIA Services Toolkit (September 2011).</p>
  
  <p>Anyone seen anything like this?
  Any help appreciated.</p>