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

Call Stack:
    2.2983     236912   1. {main}() /home/gongquiz_blog/www/index.php:0
    2.2984     238200   2. require('/home/gongquiz_blog/www/_common.php') /home/gongquiz_blog/www/index.php:2
    2.2990     272368   3. include_once('/home/gongquiz_blog/lib/common.php') /home/gongquiz_blog/www/_common.php:3
    2.3497    1143160   4. dbConn->__construct() /home/gongquiz_blog/lib/common.php:68
    2.3500    1159568   5. log_e() /home/gongquiz_blog/lib/common/dbConn.class.php:48
    4.8710    1354088   6. error_::log_e() /home/gongquiz_blog/lib/libf.php:563
    4.8712    1355808   7. error_::log() /home/gongquiz_blog/lib/common/error_.class.php:81