Some pics of the form in design and form view might help focus responses. Maybe a popup and modal form based on the sku table where user adds a sku and a type, assuming you want a user to be able to add types as well as skus. Sku types are probably best off being in their own table. In that case, they should be picking the type from a combo, typing in the sku in a textbox, and the tblSkuType PK value (autonumber) would be what gets stored along with the sku the user enters. So info about your tables would be a good idea as well. Perhaps a pic of the relationships window if you created relationships.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.