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

Call Stack:
    1.9352     234592   1. {main}() /home/gongquiz_blog/www/index.php:0
    1.9353     235880   2. require('/home/gongquiz_blog/www/_common.php') /home/gongquiz_blog/www/index.php:2
    1.9358     270048   3. include_once('/home/gongquiz_blog/lib/common.php') /home/gongquiz_blog/www/_common.php:3
    1.9515    1140920   4. dbConn->__construct() /home/gongquiz_blog/lib/common.php:68
    1.9519    1157344   5. log_e() /home/gongquiz_blog/lib/common/dbConn.class.php:48
    1.9543    1351832   6. error_::log_e() /home/gongquiz_blog/lib/libf.php:563
    1.9545    1353560   7. error_::log() /home/gongquiz_blog/lib/common/error_.class.php:81