Parallel computing for COMSOL with MATLAB

I definited a function by COMSOL .m file , whose varibles are geometrical parameters of model. Then, geometrical parameters are optimized by a genetic algorithm written by matlab. There are big computional costs, therefore I want to use a parallel computing for MATLAB. But occur errors when calling function in parallel environment. Without error in serial environment (is for not parfor), this is why?

matlab pool open;
parfor i=1:NP
fitnessX(i)=optimization(X(i,:));
end
matlab pool close;
??? Error using ==> parallel_function at 598
Error in ==> optimization at 10
Undefined variable "ModelUtil" or class "ModelUtil.create".

where optimization is the function ,

function Q = optimization(X)
import com.comsol.model.*
import com.comsol.model.util.*
model = ModelUtil.create('Model');
model.param.set('mug', '2.1e-5[Pa*s]');
model.param.set('kF', '1e-10[m^2]');
model.param.set('k', '1e-18');...
...................................................