the first witcher game doesn't lounch, unless I'm connected, and i can't use internet all the time. Is there a file i did not install? thanks

Did you try going the the folder where the game is installed ...\The Witcher Enhanced Edition Director's Cut\System
and starting it from witcher.exe in the \system folder?

Yes, i did. and i'll say that the witcher 2 and the witcher: adventure game, do work offline

I just tried The Witcher Enhanced Edition Director's Cut then with my modem disconnected, and it works fine without the internet.
The only thing I can think of is that it is GOG Galaxy related (I don't use Galaxy)
If your using Galaxy, it might be worth uninstalling the game and then downloading it using the offline installers.

Does it give you an error message when you try to run it offline?

no, it didn't, and i don't know how, but the game is working from yesterday...thanks for your help.