Installing the game.

Version 3.1 doesn't work on widescreen monitors.

I don't understand what you're talking about. If you're talking about offline play... I currently have a widescreen monitor, and I haven't had any problems with it (for version 3.1).

If you're talking about online play... I tried playing arena through Ubisoft twice. The first time, there were no problems, but the second time, the map loaded, the connection was established, but my computer froze (by the way, this was the only time my computer froze).
Then I installed Hamachi... and there were no problems.

Therefore, I think the problem is not with the monitor, but rather with the internet or Ubisoft.