Error when approver change request on ITShop

Hello! 

1IM v8.1

On portal ITShop approver want change request and add second product. When click send the approver get error: 

"An exception has occurred while executing the form method F0_ctl00_ControlRef8_ControlRef15_ControlRef15_ControlRef8b_Main_Main_Container6_Container7_Button4_Method.
Employee 'Моисеев А.В., Главный специалист (moiseev_av)' has no requests in the cart." 
Any ideas?