Error in loading model I get a certain error in loading a model and I would like to understand what it is saying to fix the problem. 

I am using Meshio add in to input a pmd/pmx model from the animation program MMD into Blender  and it gives me this. Other models have been successfully imported before and they work like a charm.   

Help will be appreciated.
The line p_bone=pose.bones[b.name] is giving the error key "" not found. The two quotes after key indicate that b.name is an empty string which is not a key in the pose.bones dictionary.

That might indicate that one of the bones does not have a name, it could also indicate that a bone has an unusual or non-text character that is causing an error when reading it into a string.

Another possibility is a zero sized bone, blender doesn't retain bones that have zero length, this means as the bone was initially created blender deleted it and then when it was referenced again later you get an error.