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

Call Stack:
    1.2980     236400   1. {main}() /home/gongquiz_blog/www/index.php:0
    1.2980     237688   2. require('/home/gongquiz_blog/www/_common.php') /home/gongquiz_blog/www/index.php:2
    1.2983     271856   3. include_once('/home/gongquiz_blog/lib/common.php') /home/gongquiz_blog/www/_common.php:3
    4.7125    1142552   4. dbConn->__construct() /home/gongquiz_blog/lib/common.php:68
    4.7127    1158952   5. log_e() /home/gongquiz_blog/lib/common/dbConn.class.php:48
    4.7153    1353456   6. error_::log_e() /home/gongquiz_blog/lib/libf.php:563
    4.7155    1355176   7. error_::log() /home/gongquiz_blog/lib/common/error_.class.php:81