or

[NullReferenceException: Object reference not set to an instance of an object.]
Telerik.Web.UI.GridBoundColumn.PrepareFieldName(IEnumerable enumerable, IQueryable queryable, String fieldName, Type dataType) +35
Telerik.Web.UI.GridBoundColumn.GetAggregate(IEnumerable enumerable, IQueryable queryable, String fieldName, Type dataType, GridAggregateFunction func) +26
Telerik.Web.UI.GridBoundColumn.ApplyAggregates35(TableCell cell, String footerText) +323
Telerik.Web.UI.GridBoundColumn.cell_DataBinding(Object sender, EventArgs e) +491
System.Web.UI.Control.OnDataBinding(EventArgs e) +99
System.Web.UI.Control.DataBind(Boolean raiseOnDataBinding) +206
System.Web.UI.Control.DataBind() +12
System.Web.UI.Control.DataBindChildren() +204
System.Web.UI.Control.DataBind(Boolean raiseOnDataBinding) +216
System.Web.UI.Control.DataBind() +12
Telerik.Web.UI.GridItem.SetupItem(Boolean dataBind, Object dataItem, GridColumn[] columns, ControlCollection rows) +539
Telerik.Web.UI.GridTableView.CreateControlHierarchy(Boolean useDataSource) +726
Telerik.Web.UI.GridTableView.CreateChildControls(IEnumerable dataSource, Boolean useDataSource) +471
System.Web.UI.WebControls.CompositeDataBoundControl.PerformDataBinding(IEnumerable data) +59
System.Web.UI.WebControls.DataBoundControl.OnDataSourceViewSelectCallback(IEnumerable data) +111
System.Web.UI.DataSourceView.Select(DataSourceSelectArguments arguments, DataSourceViewSelectCallback callback) +29
System.Web.UI.WebControls.DataBoundControl.PerformSelect() +149
Telerik.Web.UI.GridTableView.PerformSelect() +4
System.Web.UI.WebControls.BaseDataBoundControl.DataBind() +70
Telerik.Web.UI.GridTableView.DataBind() +304
Telerik.Web.UI.RadGrid.DataBind() +77
Telerik.Web.UI.RadGrid.AutoDataBind(GridRebindReason rebindReason) +132
Telerik.Web.UI.RadGrid.OnLoad(EventArgs e) +120
System.Web.UI.Control.LoadRecursive() +47
System.Web.UI.Control.LoadRecursive() +131
System.Web.UI.Control.LoadRecursive() +131
System.Web.UI.Control.LoadRecursive() +131
System.Web.UI.Control.LoadRecursive() +131
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1436
