找了半天哪里出问题了,原来在install的手sql语句
INSERT INTO `onethink_category` VALUES ('4', 'default_topic', '默认分类', '3', '0', '10', '', '', '', '', 'Article/lists_topic', 'Article/Article/detail_topic', '', '1,2', '2', '0', '1', '1', '1', '1', '1', '', '1379475068', '1381544681', '1');
默认分类的讨论,它允许的应该是2文章,和3段落