Error in the NPC formula. 

The actual formula I used for the toy example calculation and in the experiment is:
NPC = [PC_R(a_i,a_j)+PC_R^-1(a_j,a_i)]/[PC_R(a_i,a_i)+PC_R(a_j,a_j)] (Refered as PathSim measure in my VLDB'11 paper). 
So PC_R(J;J)=7 and PC_R(M;M)=9 in the toy example.