Fatal error: Class 'Client' not found in /home/gongquiz_blog/lib/common/error_.class.php on line 92

Call Stack:
    5.1108     236192   1. {main}() /home/gongquiz_blog/www/index.php:0
    5.1109     237480   2. require('/home/gongquiz_blog/www/_common.php') /home/gongquiz_blog/www/index.php:2
    5.1113     271648   3. include_once('/home/gongquiz_blog/lib/common.php') /home/gongquiz_blog/www/_common.php:3
    5.1209    1142400   4. dbConn->__construct() /home/gongquiz_blog/lib/common.php:68
    5.1459    1158808   5. log_e() /home/gongquiz_blog/lib/common/dbConn.class.php:48
    5.1476    1353344   6. error_::log_e() /home/gongquiz_blog/lib/libf.php:563
    5.1478    1355064   7. error_::log() /home/gongquiz_blog/lib/common/error_.class.php:81