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

Call Stack:
    3.4927     238328   1. {main}() /home/gongquiz_blog/www/index.php:0
    3.4928     239616   2. require('/home/gongquiz_blog/www/_common.php') /home/gongquiz_blog/www/index.php:2
    3.4930     273784   3. include_once('/home/gongquiz_blog/lib/common.php') /home/gongquiz_blog/www/_common.php:3
    3.5003    1144480   4. dbConn->__construct() /home/gongquiz_blog/lib/common.php:68
    3.5005    1160888   5. log_e() /home/gongquiz_blog/lib/common/dbConn.class.php:48
    3.5018    1355384   6. error_::log_e() /home/gongquiz_blog/lib/libf.php:563
    3.5020    1357128   7. error_::log() /home/gongquiz_blog/lib/common/error_.class.php:81