An error occurred while attempting to change modules while starting up LR 4.1. New install on a new MBP first time trying to start up
Just a guess, but since everything is new, perhaps you have some sort of permissions problem.
Make sure your user has write access to all the locations mentioned in this link:
I think "An error occurred attempting to change modules" is the (non-informative) error. Often that's caused by broken presets, but the OP evidently hasn't had time to break any.
I guess another attempt at a fix would be to re-install.