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

Call Stack:
    2.1030     236896   1. {main}() /home/gongquiz_blog/www/index.php:0
    2.1031     238184   2. require('/home/gongquiz_blog/www/_common.php') /home/gongquiz_blog/www/index.php:2
    2.1033     272352   3. include_once('/home/gongquiz_blog/lib/common.php') /home/gongquiz_blog/www/_common.php:3
    2.1657    1143096   4. dbConn->__construct() /home/gongquiz_blog/lib/common.php:68
    3.5974    1159528   5. log_e() /home/gongquiz_blog/lib/common/dbConn.class.php:48
    7.2884    1354032   6. error_::log_e() /home/gongquiz_blog/lib/libf.php:563
    7.2886    1355760   7. error_::log() /home/gongquiz_blog/lib/common/error_.class.php:81