Error in EWM on posting expected good reciept

Dear All,

                   On posting expected goods receipt from ECC , i am getting the following error in log .

@5C\QError@ Messages for Item: GRN 1

@5C\QError@ Field Item: Product is a required field for the action HDR: Activate Document              

                     Due to this on search of purchase order in /n/SCWM/GRPE , i am not getting the corresponding EGR in EWM. Could you please let me   know the error cause.

Thanks,

Shubh.