ReportSection Object not initialized

Hi,

I'm trying to overwrite footer method of AX report. But I keep getting ReportSection Object not initialized error. Where could be the problem?

public void footer(ReportSection _footerSection, tableId _tableId, fieldId _fieldId)
{
    ;
    info(int2str(_footerSection.controlCount()));
    super(_footerSection, _tableId, _fieldId);
}