Automatic Weight Error

Hey there, i’m pretty new to Blender/Rigging.
I’m almost done with my Model and now i’m getting the typical “Bone Heating” error.
I tried everything that several YouTube Videos said, but nothing worked.
Maybe you guys can help me.

.blend file http://pasteall.org/blend/index.php?id=49406

The mesh is a mess. Switch to edit, ctrl-alt-shift-m select non-manifold. You’ve got a bunch of edges linking 3+ faces. Maybe you removed doubles without thinking about it? This is a serious problem that will cause issues for your model in a lot of ways, and autoweight failure is one of those ways. Fix the mesh.