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

Call Stack:
    2.0232     238008   1. {main}() /home/gongquiz_blog/www/index.php:0
    2.0233     239296   2. require('/home/gongquiz_blog/www/_common.php') /home/gongquiz_blog/www/index.php:2
    2.0235     273464   3. include_once('/home/gongquiz_blog/lib/common.php') /home/gongquiz_blog/www/_common.php:3
    2.0619    1144056   4. dbConn->__construct() /home/gongquiz_blog/lib/common.php:68
    2.0621    1160464   5. log_e() /home/gongquiz_blog/lib/common/dbConn.class.php:48
    2.0637    1354984   6. error_::log_e() /home/gongquiz_blog/lib/libf.php:563
    2.0638    1356704   7. error_::log() /home/gongquiz_blog/lib/common/error_.class.php:81