An exception occured while bootstrapping the application.

SQLSTATE[HY000]: General error: 1364 Field 'user_name' doesn't have a default value
Stack Trace:
#0 /usr/www/users/lateinw/library/Zend/Db/Statement.php(300): Zend_Db_Statement_Pdo->_execute(Array)
#1 /usr/www/users/lateinw/library/Zend/Db/Adapter/Abstract.php(479): Zend_Db_Statement->execute(Array)
#2 /usr/www/users/lateinw/library/Zend/Db/Adapter/Pdo/Abstract.php(238): Zend_Db_Adapter_Abstract->query('INSERT INTO `us...', Array)
#3 /usr/www/users/lateinw/library/Zend/Db/Adapter/Abstract.php(574): Zend_Db_Adapter_Pdo_Abstract->query('INSERT INTO `us...', Array)
#4 /usr/www/users/lateinw/library/Zend/Db/Table/Abstract.php(1052): Zend_Db_Adapter_Abstract->insert('user', Array)
#5 /usr/www/users/lateinw/library/Zend/Db/Table/Row/Abstract.php(467): Zend_Db_Table_Abstract->insert(Array)
#6 /usr/www/users/lateinw/library/Zend/Db/Table/Row/Abstract.php(438): Zend_Db_Table_Row_Abstract->_doInsert()
#7 /usr/www/users/lateinw/library/Dkplus/Model/Row/Db.php(73): Zend_Db_Table_Row_Abstract->save()
#8 /usr/www/users/lateinw/library/Dkplus/Model/Row/Abstract.php(458): Dkplus_Model_Row_Db->_save()
#9 /usr/www/users/lateinw/dkplus/application/modules/default/models/Row/User.php(250): Dkplus_Model_Row_Abstract->save()
#10 /usr/www/users/lateinw/dkplus/application/modules/default/models/User.php(224): Model_Row_User->save()
#11 /usr/www/users/lateinw/library/Dkplus/Model/Abstract.php(436): Model_User->fetchInnerRow()
#12 /usr/www/users/lateinw/dkplus/application/Bootstrap.php(137): Dkplus_Model_Abstract->__get('locale')
#13 /usr/www/users/lateinw/library/Zend/Application/Bootstrap/BootstrapAbstract.php(666): Bootstrap->_initLocaleUser()
#14 /usr/www/users/lateinw/library/Zend/Application/Bootstrap/BootstrapAbstract.php(619): Zend_Application_Bootstrap_BootstrapAbstract->_executeResource('localeuser')
#15 /usr/www/users/lateinw/library/Zend/Application/Bootstrap/BootstrapAbstract.php(583): Zend_Application_Bootstrap_BootstrapAbstract->_bootstrap(NULL)
#16 /usr/www/users/lateinw/library/Zend/Application.php(355): Zend_Application_Bootstrap_BootstrapAbstract->bootstrap(NULL)
#17 /usr/www/users/lateinw/dkplus/public/index.php(39): Zend_Application->bootstrap()
#18 {main}