Shortly after placing 8 redwood slabs upside down (at the top-half of a block) I decided to move them and started breaking them and a vanilla access ladder with a mythril axe (Simple Ores 2). While breaking the ladder, Minecraft crashed with the crash report posted at http://www.minecraftforum.net/topic/1753754-16xnatura/page__st__840#entry25286718.

After the crash, I cannot even load my world without it crashing again. Even editing out the redwood slabs (suspected culprit) in MCEdit does not stop the crash. The item in question has metadata = 11. I also note that MCEdit shows the redwood slabs I thought I had broken with the axe as still in position.

if you have any screenshots of any of this it might help me track this down

I'm not sure how useful a screenshot of my launcher telling me I crashed would be ;-)

My crash log is posted at http://www.minecraftforum.net/topic/1753754-16xnatura/page__st__840#entry25286718

Minecraftforum poster Aalandriel thinks they found the problem in your github source, described in this post: http://www.minecraftforum.net/topic/1753754-16xnatura/page__st__840#entry25577526