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

Call Stack:
    2.8807     233064   1. {main}() /home/gongquiz_blog/www/index.php:0
    2.8807     234352   2. require('/home/gongquiz_blog/www/_common.php') /home/gongquiz_blog/www/index.php:2
    2.8810     268936   3. include_once('/home/gongquiz_blog/lib/common.php') /home/gongquiz_blog/www/_common.php:3
    2.9254    1141448   4. dbConn->__construct() /home/gongquiz_blog/lib/common.php:68
    2.9256    1157880   5. log_e() /home/gongquiz_blog/lib/common/dbConn.class.php:48
    2.9373    1352512   6. error_::log_e() /home/gongquiz_blog/lib/libf.php:563
    2.9396    1354248   7. error_::log() /home/gongquiz_blog/lib/common/error_.class.php:81