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

Call Stack:
    1.5956     236528   1. {main}() /home/gongquiz_blog/www/index.php:0
    1.5956     237816   2. require('/home/gongquiz_blog/www/_common.php') /home/gongquiz_blog/www/index.php:2
    1.5959     271984   3. include_once('/home/gongquiz_blog/lib/common.php') /home/gongquiz_blog/www/_common.php:3
    1.6032    1142656   4. dbConn->__construct() /home/gongquiz_blog/lib/common.php:68
    1.6033    1159104   5. log_e() /home/gongquiz_blog/lib/common/dbConn.class.php:48
    1.6047    1353648   6. error_::log_e() /home/gongquiz_blog/lib/libf.php:563
    1.6048    1355376   7. error_::log() /home/gongquiz_blog/lib/common/error_.class.php:81