SetCurrentRowOnSelection throws 'Could not find a record matching the provided DataKey' error

Hi,

Despite the fact that EP works fine on deveplopment environment it keeps throwing errors on production environment. There is a lookup wich gets data from dataset into gridview. When this.AxGridView1.SetCurrentRowOnSelection = true is set and user selects another row in in gridview for editing the page throws error:

Could not find a record matching the provided DataKey.

System.Collections.Generic.KeyNotFoundException
   at Microsoft.Dynamics.Framework.Data.Ax.DataSetView.SetCurrent(AxViewDataKey dataKey)
   at Microsoft.Dynamics.Framework.Portal.UI.WebControls.AxDataSourceView.ExecuteUpdate(IDictionary keys, IDictionary values, IDictionary oldValues)
   at System.Web.UI.DataSourceView.Update(IDictionary keys, IDictionary values, IDictionary oldValues, DataSourceViewOperationCallback callback)
   at System.Web.UI.WebControls.GridView.HandleUpdate(GridViewRow row, Int32 rowIndex, Boolean causesValidation)
   at System.Web.UI.WebControls.GridView.HandleEvent(EventArgs e, Boolean causesValidation, String validationGroup)
   at System.Web.UI.WebControls.GridView.RaisePostBackEvent(String eventArgument)
   at Microsoft.Dynamics.Framework.Portal.UI.WebControls.AxGridView.RaisePostBackEvent(String eventArgument)
   at System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument)
   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

How to fix this? It really became a big headache...

Thanks in advance