Its always better to attach the worksheet itselft rather than just a picture.
Are you aware that Prime uses two different types of indices - literal indices and vector/matrix indices?
Chances are that you used the wrong ones.
A vector index is just an integer. So you could not use something like z.k1 but rather would use z.10*k+1
Furthermore you have to know that if you define z.11:=... you are defining a 12 element vector (assuming you have not changed the value of ORIGIN which is 0 by default). Unless you have them defined before, all other elements of the vector z (z.0, z.1 ... z.10) are set to zero.
