If the universe is flat, and therefore infinite, yes it means that most probably there are an infinite number of identical duplicates of you. It does not mean, however, that there are any duplicates of you that make a particular typo. I should think that there are an infinite number of such duplicates for any given typo, BUT it may also be the case that such worlds are impossible. E.g., physics is deterministic enough and chaotic enough that there is no slight nudge to the initial conditions of a world that will result in such a minor eventual difference to occur.

I.e., just because there are an infinite number of parallel worlds, doesn't mean that every imaginable thing occurs in them. What occurs in a parallel world, must be possible.