Error CS0246 in GameManager (Roguelike 2D tutorial)

Hi,

I'm doing the Roguelike 2D game, and and my GameManager script is now supposed to look as it does here at 1:18 in the tutorial:

https://youtu.be/7NYXBUWmFvU?t=1m18s

My own code looks like this:

But I'm getting error CS0246: The type or namespace name "BoardManager" could not be found. Are you missing a using directive or an assembly reference?

I've gone through the previous parts of the tutorial and have a C# BoardManager script that doesn't contain errors. (There was a problem with it that I couldn't figure out how to fix, so I ended up copying the code given by the tutorial to move on.)

I've seen "Add the class BoardManager to the current/same GameObject that GameManager is attached to" as advice to someone else but I had done that. In an attempt to start over, I deleted the GameObject and tried to create a new one and add GameManager&BoardManager to it, but I can't do that because I get "Can't add script: please fix compile errors before creating new script components".

Thanks.