downloaded free zip file from tierce site 01net need key

I download the game via 01net site.

"http://www.01net.com/telecharger/windows/Jeux/action/fiches/121241.html"

Battlefield 1942 is a free version

when i try to launch the game using origin , an activation key is requested.

The following message appear: "Pour jouer à DisplayName field missing from registry., vous devez d'abord l'activer sur votre Compte EA"

I need to click on "Activer le jeu"

I don't have any key to type as it is a free version.

The downloaded  file is a ZIP file with auto extract in

C:\Program Files (x86)\Origin Games\Battlefield 1942

and the directory contain the BF1942.exe file to be launch using origin

Can you help me? How can I proceed ?

regards