Index: branches/release-34/lib/MT/App/CMS.pm
===================================================================
--- branches/release-34/lib/MT/App/CMS.pm (revision 1857)
+++ branches/release-34/lib/MT/App/CMS.pm (revision 1858)
@@ -765,5 +765,5 @@
                     # to prevent MT from adding a 'entry_' prefix to
                     # the column name.
-                    $args->{sort}      = \'comment_created_on';
+                    $args->{sort}      = [ { column => \'comment_created_on' } ];
                     $args->{direction} = 'descend';
                 },