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

Call Stack:
    6.1469     237816   1. {main}() /home/gongquiz_blog/www/index.php:0
    6.1469     239104   2. require('/home/gongquiz_blog/www/_common.php') /home/gongquiz_blog/www/index.php:2
    6.1472     273272   3. include_once('/home/gongquiz_blog/lib/common.php') /home/gongquiz_blog/www/_common.php:3
    6.1545    1144040   4. dbConn->__construct() /home/gongquiz_blog/lib/common.php:68
    6.1546    1160472   5. log_e() /home/gongquiz_blog/lib/common/dbConn.class.php:48
    6.1560    1354976   6. error_::log_e() /home/gongquiz_blog/lib/libf.php:563
    6.1561    1356704   7. error_::log() /home/gongquiz_blog/lib/common/error_.class.php:81