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

Call Stack:
    1.0007     238840   1. {main}() /home/gongquiz_blog/www/index.php:0
    1.0008     240128   2. require('/home/gongquiz_blog/www/_common.php') /home/gongquiz_blog/www/index.php:2
    1.0010     274296   3. include_once('/home/gongquiz_blog/lib/common.php') /home/gongquiz_blog/www/_common.php:3
    1.0462    1145072   4. dbConn->__construct() /home/gongquiz_blog/lib/common.php:68
    1.0553    1161488   5. log_e() /home/gongquiz_blog/lib/common/dbConn.class.php:48
    4.3453    1356016   6. error_::log_e() /home/gongquiz_blog/lib/libf.php:563
    4.3454    1357736   7. error_::log() /home/gongquiz_blog/lib/common/error_.class.php:81