项目任务和项目需求不能显示已解决 悬赏5积分

点击查看项目-任务、项目-需求的时候，都提示以下错误

Fatal error: Uncaught Error: Call to a member function fetch() on null in /opt/zbox/app/zentao/lib/base/dao/dao.class.php:858 Stack trace: #0 /opt/zbox/app/zentao/module/project/model.php(1883): baseDAO->fetchPairs('project', 'project') #1 /opt/zbox/app/zentao/module/project/control.php(128): projectModel->getLimitedProject() #2 /opt/zbox/app/zentao/framework/base/router.class.php(1691): project->task('114', 'unclosed', 0, '', 0, 100, 1) #3 /opt/zbox/app/zentao/www/index.php(67): baseRouter->loadModule() #4 {main} thrown in /opt/zbox/app/zentao/lib/base/dao/dao.class.php on line 858