Robert - the error message is telling you that not enough input parameters are being supplied to your function h via fsolve. According to the documentation for fsolve, the input function fun is a function that accepts a vector x and returns a vector F, the nonlinear equations evaluated at x. So a single input only. Your h is defined with two inputs (one of which is unused, t) as
h = @(t,z) [ (-0.2)*(z(1) - z(1).^3/3 - z(2) + I); (-0.2)*(0.7*(z(1) + 0.7 - 0.8*z(2))) ];
though the error message seems to be indicating that there are three input variables, t, y and z. As neither t nor y are ever used in your function, then you should be able to define h as
h = @(z)[ (-0.2)*(z(1) - z(1).^3/3 - z(2) + I); (-0.2)*(0.7*(z(1) + 0.7 - 0.8*z(2))) ];
This assumes that I has already been initialized. Try making the above change and see what happens!
