Aspect ratio is not preserved in widescreen mode.

Now, I'll check if the game supports your resolution, and I'll tell you this: if possible, download the Nvideo OMEGA Driver, it's a special driver optimized for games... you'll ask where to find it, and I'll answer: search!

Added 15 minutes later
Here's what I read on Nival

As I understand from the latest post, everything works at your resolution, but things are worse with other resolutions, so this is a bug of the programmers, therefore I think you should install Lords of the North, because they were obliged to include widescreen resolutions there.