Issue while defining columns for telerik mvc grid

[test]

I m getting the following error when i try to define the columns for the grid:
Unable to cast object of type 'System.Linq.Expressions.ConstantExpression' to type 'System.Linq.Expressions.ParameterExpression'
Can someone tell me how i can bind the columns in this case?
I am trying to add columns for the grid as:

List<Details> posEquity = Model.ListPositions.FindAll(delegate(Details Details) { return accPosDetails.SecurityType; });

                  


                   @if (posEquity != null && posEquity.Count > 0)

                   {

                       <div>

                       @foreach (Details pos in posEquity)

                    {

                        Html.Telerik().Grid(posEquity).Name("grdPersonView")

                        .Columns(columns =>

                         {

                             columns.Bound(p => pos.AccountNumber);

                             columns.Bound(p => pos.CashValue);

                             columns.Bound(p => pos.CashSuperscript);

                         })

                       .Render();

                       }

                      


                       </div>