fmincon returns different results depending on the PC

I am using the fmincon command to solve an optimization problem. The initial conditions are the same, and the options (TolX, Algorithm, TolFun...) too. The two machines where this code is running are:

1. Intel Pentium i7-920, MS Windows 7, RAM 4 GB
2. Intel Atom n270, MS Windows 8, RAM 1 GB

Often, in addition to the different results, the code returns me an error on the first PC:

"fmincon stopped because the size of the current step is less than the default value of the step size tolerance but constraints were not satisfied to within the default value of the constaint tolerance."

Answer 1

[Matt J]

Sounds to me either like a non-differentiability effect.