pfff, sorry but it doesn't work either. It says thta it cannot find the value because it doesn't exist. The thing is the subform has more than one productId:

Subform:
orderdetailsId
orderId(bound it to the FormNewOrders)
orderdetails.productId(see FormProducts)
motorId
price
extras
products.productId (to show other items from the Products table, here under)
location (seeFormProducts)
ref(see FormProducts)
...

I put this:
[VBA]
DoCmd.OpenForm stDocName, , , , acFormAdd ' Remove reference to stLinkCriteria
Forms!NewOrders.Subform!Products.ProductId = Me.ProductId
DoCmd.Close acForm, "Products"
[/VBA]