DTW Min & Max Stock levels not updating

Good Day,

Please assist, I need to update min and max stock levels for the same items in three different items.

I am using DTW OITW as Inventory is managed by w/h.

I keep getting the error message item already exists. I started the Linenum with 0.

I used item code, minstock and maxstock.

Please assist.

Regards,

Izak