Exception: ro.frontend.messages.php not found!

#0 /home/varnabg/public_html/visit/classes/phpCoreLib2/I18N/DInt.php(49): DPHPMessageSource->loadCategory('frontend', 'ro')
#1 /home/varnabg/public_html/visit/classes/phpCoreLib2/I18N/DInt.php(95): DPHPMessageSource->translate('frontend', '\xD0\x92\xD1\x85\xD0\xBE\xD0\xB4 \xD0\xBF\xD0\xBE\xD1\x82...', 'ro')
#2 /home/varnabg/public_html/visit/classes/phpCoreLib2/I18N/DInt.php(137): I18N->translate('frontend', '\xD0\x92\xD1\x85\xD0\xBE\xD0\xB4 \xD0\xBF\xD0\xBE\xD1\x82...', Array, 'ro')
#3 /home/varnabg/public_html/visit/classes/account.php(129): DInt::tr('frontend', '\xD0\x92\xD1\x85\xD0\xBE\xD0\xB4 \xD0\xBF\xD0\xBE\xD1\x82...')
#4 [internal function]: DAccount->_login()
#5 /home/varnabg/public_html/visit/classes/account.php(70): call_user_func(Array)
#6 /home/varnabg/public_html/visit/classes/_libs/DUserFormAction.php(90): DAccount->_formAction()
#7 /home/varnabg/public_html/visit/classes/_libs/DUserFormAction.php(130): DUserFormAction->onScreen()
#8 /home/varnabg/public_html/visit/classes/phpCoreLib2/Web/MVC/DController.php(221): DUserFormAction->run()
#9 /home/varnabg/public_html/visit/classes/phpCoreLib2/Web/MVC/DController.php(112): DController->handleData()
#10 /home/varnabg/public_html/visit/index.php(112): DController->displayResults()
#11 {main}