Hi,
The column ask for the an "id" but when you create a new product, you can't know the "id" of the product you will create (because you add a new one, you're not updating an existing product).
That's why, the column also accept a "product_code" which is unique in the database.
When the import see that the "id" is not a number, it will look in the "code" to find the good one.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.