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

Call Stack:
    4.0782     237736   1. {main}() /home/gongquiz_blog/www/index.php:0
    4.0783     239024   2. require('/home/gongquiz_blog/www/_common.php') /home/gongquiz_blog/www/index.php:2
    4.0953     273192   3. include_once('/home/gongquiz_blog/lib/common.php') /home/gongquiz_blog/www/_common.php:3
    4.1490    1143840   4. dbConn->__construct() /home/gongquiz_blog/lib/common.php:68
    4.1492    1160240   5. log_e() /home/gongquiz_blog/lib/common/dbConn.class.php:48
    4.1509    1354776   6. error_::log_e() /home/gongquiz_blog/lib/libf.php:563
    4.1510    1356496   7. error_::log() /home/gongquiz_blog/lib/common/error_.class.php:81