Hey @roadapathy, thanks for getting through to us, welcome to forums and sorry to hear about the difficulty you ran into with gifting the game to your friend(s).
If you have purchased game copy from Humble Bundle and you have been issued with Activation Key that is only active in certain regions, I am afraid it is not something we'd be able to assist you with and you would need to get through to their support and looking at gifting options as well as see if you're able to get Activation Key replacement which would have no regional restrictions in Argentina.
Apologies for not being able to assist you with this one and do hope you will get it sorted.
Should you have any further queries, let us know!