Trivial stuff:
The 0 needs to be a vector of zeros and the "=" needs to be "==". Put a space between names that are being multiplied. Put a period (see "Dot") between things that will be vector/matrix multiplied.
http://reference.wolfram.com/mathematica/ref/Dot.html
Bigger issue:
V.matA is a vector and matB is a matrix. How do they add?
