Warning: Parameter 1 to plgVmShipmentWeight_countriesstates::plgVmOnSelectCheckS

[theopap]

Hello

I am geting the following errors after the client completes an order.
I would like your help on how to fix this

Warning: Parameter 1 to plgVmShipmentAcscourier::plgVmOnSelectCheckShipment() expected to be a reference, value given in /home/...../public_html/libraries/joomla/event/event.php on line 70

Warning: Parameter 1 to plgVmShipmentWeight_countriesstates::plgVmOnSelectCheckShipment() expected to be a reference, value given in /home/..../public_html/libraries/joomla/event/event.php on line 70

Warning: Parameter 1 to plgVmShipmentWeight_countries::plgVmOnSelectCheckShipment() expected to be a reference, value given in /home/..../public_html/libraries/joomla/event/event.php on line 70

Thanks in advance