fix problem with order of approximation in estimation

matlab/dynare_estimation_init.m

@@ -61,14 +61,12 @@ for i = 1:size(M_.endo_names,1)
 end
 
 %% Set the order of approximation to one (if needed).
-if options_.order > 1
-    if ~exist('particle','dir')
+if options_.order > 1 && ~isfield(options_,'nonlinear_filter')
     disp('This version of Dynare cannot estimate non linearized models!')
     disp('Set "order" equal to 1.')
     disp(' ')
     options_.order = 1;
 end
-end
 
 % Set options_.lik_init equal to 3 if diffuse filter is used or
 % kalman_algo refers to a diffuse filter algorithm.