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

Call Stack:
    1.9608     236160   1. {main}() /home/gongquiz_blog/www/index.php:0
    1.9614     237448   2. require('/home/gongquiz_blog/www/_common.php') /home/gongquiz_blog/www/index.php:2
    1.9618     271616   3. include_once('/home/gongquiz_blog/lib/common.php') /home/gongquiz_blog/www/_common.php:3
    3.6113    1142360   4. dbConn->__construct() /home/gongquiz_blog/lib/common.php:68
    3.6115    1158800   5. log_e() /home/gongquiz_blog/lib/common/dbConn.class.php:48
    3.6136    1353256   6. error_::log_e() /home/gongquiz_blog/lib/libf.php:563
    3.6138    1354984   7. error_::log() /home/gongquiz_blog/lib/common/error_.class.php:81