Oat Flour for pasta not rolling well?
Pasta relies on gluten development for its strength and structure.  Only wheat and its close relatives have the necessary precursor proteins, glutenin and gliadin, from which gluten is formed.

You simply will not be able to make pasta from 100% oat flour using a recipe designed for wheat flour, as oats do not contain gluten (well, technically, its precursors).

If you desire a gluten free pasta, you should search for recipes specifically for that purpose.  They are often bound together with xantham gum or other hydrocolloids.

If you are just looking for an interesting pasta as an alternative to the more traditional ones, you need to make sure you have enough gluten available to support the structure (and overcome the weakening that will come from using oat flour, which will physically interrupt the gluten strands).  I would suggest making sure you are using high protein wheat flour (such as bread flour), and only substituting a portion (no more than say 25%, and you might want to start with smaller amounts to see how it works) with oat flour.  I haven't tried this, so you will need to experiment to find a good balance between oat flavor, and the ability for the pasta to hold its shape and structure.