Run-time error

[jcaptchaos2]

I am getting a runtime error -2147352567(80020009) while using this code if the employee types a number into a combo box instead of using the scanner, is there a way to stop the error from popping up?

Private Sub Shop_Order_Number_AfterUpdate()
   Static abort As Boolean
    If abort Then abort = False: Exit Sub
    Op_Number = Mid(Shop_Order_Number, 6, 3)
    abort = True
    Shop_Order_Number = Left(Shop_Order_Number, 5)
    Item_Number = DLookup("[itemnumber]", "[shoporderstatus]", "[shoporderstatus]![shopordernumber]= " & [Forms]![Shop Floor Data Entry]![Shop Order Number])
End Sub