Error in ComboBox

Error in ComboBox

Hi All.

When I loading a combo box this error appears to me. Emphasize that started giving this error when I did the migration from version 7 to 8.

rowNumber must be 0 or a positive integer value
Parameter name: rowNumber
Actual value was -1.

 at OutSystems.HubEdition.RuntimePlatform.Db.RecordList.SetPosition(Int32 rownumber)
   at sseANA_SGPA.Flows.FlowImportExport.WBlkImportBranch.selarpPT_dropDown_valueChanged(Object sender, EventArgs e)
   at System.Web.UI.WebControls.ListControl.OnSelectedIndexChanged(EventArgs e)
   at OutSystems.HubEdition.WebWidgets.DropDownList.#gGb()
   at System.Web.UI.Page.RaiseChangedEvents()
   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

Please help!

Eduardo Caetano