To those asking what I did, I turned printed with only 2 shells and slowed the print down.

thethin wall infill problem is solved with the latest version of slic3r go to slic3r.org to get the new version

Turn off any extra shells - too many shells with skinny walls like these will create infill zones that are too small to fill.  

It looks like that was a slicing problem, that would sometimes happen to me with slic3r. Now I use Keep It Simple Slicer (Kisslicer) it's free but there is a pro version for a few options that you don't really need. It slices things really fast too, yoda takes less that 10 minutes I think. I haven't had any slicing problems with Kisslicer like the picture.  

What were your print settings?  And what's the scale?  Also it looks like (at least in pleasant 3D and Netfab) it's not solid in the "B" openings.