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

Call Stack:
    2.6333     235248   1. {main}() /home/gongquiz_blog/www/index.php:0
    2.6334     236536   2. require('/home/gongquiz_blog/www/_common.php') /home/gongquiz_blog/www/index.php:2
    2.6587     270704   3. include_once('/home/gongquiz_blog/lib/common.php') /home/gongquiz_blog/www/_common.php:3
    3.7506    1141360   4. dbConn->__construct() /home/gongquiz_blog/lib/common.php:68
    3.7710    1157776   5. log_e() /home/gongquiz_blog/lib/common/dbConn.class.php:48
    3.7758    1352272   6. error_::log_e() /home/gongquiz_blog/lib/libf.php:563
    3.7759    1354000   7. error_::log() /home/gongquiz_blog/lib/common/error_.class.php:81