There were a number of problems: 1. You had some multiply signs missing. 2. Your equations didn't match the ones on the right-hand page (you'd cubed 12 wherever it appeared). 3. M14 and 15 won't allow mixed units in a single vector. 4. Your initial guesses were such that the solve block wouldn't converge.
I've corrected these and the solve block works. However, the results are very sensitive to the initial guesses, so I would suggest you see if there is any way of reformulating the equations to remove this sensitivity.
Alan
