^
I load a campaign and I get that error, I installed using the BI.exe (there may be a connection)
When I load a custom battle, I get returned to the main menu.
If you went to the Skyrim forums you'll see a lot posts about how it's somehow been watered down and hampered by money men making the decisions. Fact is, it's a great game and people still complain. It's the same thing as the TW franchise.