Where do i get the activation code to play multiplayer

Do you mean a serial key? If so, go to the game page in your library, click 'View Downloads', then click 'More', then 'Serial keys'.

Hope this helps.

Thanks but the serial key doesn,t work .When i try to go on the network it says it requires an activation code which is apparently all numbers because it won,t accept any letters.

Sorry that didn't help. It might be worth contacting support - http://www.gog.com/support - hopefully they'll be able to sort it.

Thanks anyway any help is always appreciated

Which game? For Two Worlds 2, you should be able to get the multiplayer key on your game page as mentioned above. For Two Worlds 1, you need to contact support to get it. There's a specific question you can select on the support page that says "request multiplayer key" or similar. Do that and you'll get an email back from GOG in a few business days with your key. I successfully got a key this way, although I never ended up trying to play multiplayer.