Hi, I am trying to access previous selected sibling row, to do some validations for ultrawebgrid 6.1

this is what I wrote. I am getting the current row, but igtbl_getPrevSibRow function is not returning anything. any help will be appreciated

 functionUltraWebGrid1_AfterRowInsertHandler(gridName, rowId, index)
{
var prevRow;
var curRow;
curRow = igtbl_getRowById(rowId);
prevRow = igtbl_getPrevSibRow(gridName,curRow);
}