Updating Items with DTW : error valid value

hello,

When I try to update one item with DTW I got one valid format error like this :

"" is not a valid value for field "SellItem" the valid value are 'Y' 'Yes' 'N' 'No' application-defined or object-defined error65171.

and this is my CSV file :

RecordKey ItemCode ItemName ItemsGroupCode BarCode SalesVATGroup PurchaseItem SalesItem InventoryItem

1; AB1072; IDE_CISL_HOBBY_1033; 101 ; 5010356990356 ; C4 ;Y ;Y ;Y

So the same error came for the Last Three fields.

Did someone have a solution ?

JPL