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

Call Stack:
    1.6496     238280   1. {main}() /home/gongquiz_blog/www/index.php:0
    1.6498     239568   2. require('/home/gongquiz_blog/www/_common.php') /home/gongquiz_blog/www/index.php:2
    1.6503     273736   3. include_once('/home/gongquiz_blog/lib/common.php') /home/gongquiz_blog/www/_common.php:3
    1.6661    1144576   4. dbConn->__construct() /home/gongquiz_blog/lib/common.php:68
    1.6664    1160992   5. log_e() /home/gongquiz_blog/lib/common/dbConn.class.php:48
    1.6698    1355552   6. error_::log_e() /home/gongquiz_blog/lib/libf.php:563
    1.6702    1357288   7. error_::log() /home/gongquiz_blog/lib/common/error_.class.php:81