Well I've been working on a large landmass mod and a friend of mine decided to mess around on the construction set. Anyways he did something and now the cell will not change, I have to use the cell window to swap from one exterior cell to the other and its rather bothersome. How do I fix this?

Can you elaborate? Do you mean you can't move from one exterior cell to another in the render window (e.g. by selecting an object in an adjoining cell)? If so, there's a preferences checkmark File -> Preferences and in the Cell Load Settings, check Allow Render Window Cell Loads. If that's already checked, then I have no idea.

Thank you! That fixed it.

There is however another problem now. Now my CS will not load Bloodmoon, it errors out with messages saying that the Chunk size is to large or something, anyone know what is wrong? The game itself still works perfectly its just the CS.

Edit: Nevermind, I fixed it. Thanks for the help!