As stated in title, how can I do it? When I start Uplay it gives me an error and it's all.
You can't yet , there are still alot of bugs needed to be fixed Check out this link for more information http://www.winehq.org/pipermail/wine-bugs/2012-May/322485.html
If you really need to use this on Ubuntu , there is still one way , Install Windows 8 ( Free Version ) in Virtualbox and through that , you play the games.
you can also check out another game client that runs nativly on Linux