Is there a reason that you are using ga instead of patternsearch? The patternsearch solver is quite robust to evaluation failures. Unless you need multiobjective optimization, I strongly recommend patternsearch over ga, because it is faster, more robust, and easier to tune.
The only place where ga is better than patternsearch is that it chooses its own starting population. But you can easily set random initial points for patternsearch within bounds by using
x0 = lb + rand(size(lb)).*(ub - lb);
Good luck,
Alan Weiss
MATLAB mathematical toolbox documentation
