Warning: filemtime(): stat failed for /var/www/html/skin/frontend/base/default/css/nivo-slider/nivo-slider.css  in /var/www/html/app/code/local/Whites/Core/Model/Design/Package.php on line 19

#0 [internal function]: mageCoreErrorHandler(2, 'filemtime(): st...', '/var/www/html/a...', 19, Array)
#1 /var/www/html/app/code/local/Whites/Core/Model/Design/Package.php(19): filemtime('/var/www/html/s...')
#2 /var/www/html/app/code/local/Whites/Core/Model/Design/Package.php(51): Whites_Core_Model_Design_Package->getNewestFileTimestamp(Array)
#3 [internal function]: Whites_Core_Model_Design_Package->getMergedCssUrl(Array)
#4 /var/www/html/app/code/core/Mage/Page/Block/Html/Head.php(277): call_user_func(Array, Array)
#5 /var/www/html/app/code/core/Mage/Page/Block/Html/Head.php(208): Mage_Page_Block_Html_Head->_prepareStaticAndSkinElements('