After having followed your installation instructions, I receive the below msg.
You didn't setup any blog relationships! You have to setup them first to use Multilingual Press. For this, go to Network » Sites » and choose a blog to edit. Then go to the tab "Multilingiual Press" and set up the relationships.
I am running WP 3-5-1
How do I create the necessary blogs to set up a relationship between them?
Also, I do not have a tab 'Multilingual Press', but this may be because of the above error