fitting a surface with an error model

Hi, I have 2 matrices A and B of the same size (mxn) and an error model of the form:

E(x) = ((a/(x/2000) + b).^2) + c

the variable x is the elements of matrix B.

I want to compute another matrix of the form:

A2 = A + E(x).

My question is: how can I compute the error model parameters a,b and c and the output matrix A2 using the curve fitting toolbox or any other Matlab tool.

Thank you.