Open the "Structure" tab of the Orders table and make sure they are the same.... Try checking the "Allow Null" checkbox for the OrderShipAddress2 table.
You could also update the default value for that column to be blank.
You could also update the line on your store cart summary in database from:
$ConditionalQuery->bindColumn("OrderShipAddress2", "d", "".(WA_coalesce(array(WA_getSavedFormValue('CheckoutWizard_NewFromBlank_Default','Address_2_2'),WA_getSavedFormValue('CheckoutWizard_NewFromBlank_Default','Address_2')))) ."", "WA_DEFAULT");
to:
$ConditionalQuery->bindColumn("OrderShipAddress2", "d", "".(WA_coalesce(array(WA_getSavedFormValue('CheckoutWizard_NewFromBlank_Default','Address_2_2'),WA_getSavedFormValue('CheckoutWizard_NewFromBlank_Default','Address_2')))) ."", "WA_BLANK");
That will insert a blank entry when the field is omitted instead of trying to use the database default.
