Please, explain me, why I got this? And how to get normal one?

So, I have to minimize only one variable, but with totally insane constraints. For simplicity, I want to solve it only for n=4 and specific graph, so it will be a little bit easier than described below.

1n is a column of "1".
So, is it possible at all? I spent almost 5 hours, tried everything that is possible to google, but still can't run it. Here is what I've done(as 'D' is reserved, I used 'B' instead):

Can somebody explain me this: