The four required arguments are in my last post, you are missing systemCode.
Change
Ice.UI.App.ChgLogEntry.ChgLogArgs lfo = new Ice.UI.App.ChgLogEntry.ChgLogArgs("DMRHead", edvDMRHead.dataView[edvDMRHead.Row]["RowIdent"].ToString(), true);
to
Ice.UI.App.ChgLogEntry.ChgLogArgs lfo = new Ice.UI.App.ChgLogEntry.ChgLogArgs("Erp", "DMRHead", edvDMRHead.dataView[edvDMRHead.Row]["RowIdent"].ToString(), true);