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

Call Stack:
    1.5156     238392   1. {main}() /home/gongquiz_blog/www/index.php:0
    1.5157     239680   2. require('/home/gongquiz_blog/www/_common.php') /home/gongquiz_blog/www/index.php:2
    1.5163     273848   3. include_once('/home/gongquiz_blog/lib/common.php') /home/gongquiz_blog/www/_common.php:3
    3.3461    1144712   4. dbConn->__construct() /home/gongquiz_blog/lib/common.php:68
    3.3464    1161144   5. log_e() /home/gongquiz_blog/lib/common/dbConn.class.php:48
    4.8925    1355648   6. error_::log_e() /home/gongquiz_blog/lib/libf.php:563
    5.0265    1357376   7. error_::log() /home/gongquiz_blog/lib/common/error_.class.php:81