Fixed bug.

Frequency is passed as a member of the dates class.

src/@dates/subperiod.m

@@ -17,8 +17,8 @@ function s = subperiod(d)
 % You should have received a copy of the GNU General Public License
 % along with Dynare.  If not, see <http://www.gnu.org/licenses/>.
 
-if freq==365 || freq==1
-    error('Method not available for daily or annual frequencies.')
+if d.freq==365
+    error('Method not available for daily frequency.')
 end
 
 s = d.time(2);
\ No newline at end of file