I have been getting "Unable to update the row" while adding row 13 on SWfTable object. like

SwfWindow("Test").SwfWindow("Add Draw").SwfTable("FGrid").AddRow "IN_FEE","13".

It works fine though after clicking ok on dialog box.
Is it because of only 13 rows are visible on grid and from 13 onward scrollbar on grid has to be use. Infact i used scrollfunction to scrolldown through grid which would select or add row

could you please assist me in resolving this issue.Any help would be highly appreciated.