Can't get filling percentage

#0 /var/www/magazziniambrosi/html/includes/src/Zend_Cache_Backend_Memcached.php(408): Zend_Cache::throwException('Can't get filli...')
#1 /var/www/magazziniambrosi/html/includes/src/Zend_Cache_Backend_TwoLevels.php(530): Zend_Cache_Backend_Memcached->getFillingPercentage()
#2 /var/www/magazziniambrosi/html/includes/src/Zend_Cache_Backend_TwoLevels.php(198): Zend_Cache_Backend_TwoLevels->_getFastFillingPercentage('saving')
#3 /var/www/magazziniambrosi/html/includes/src/__default.php(64259): Zend_Cache_Backend_TwoLevels->save('a:2:{i:0;a:7:{s...', '117_APP_4E4ABDD...', Array, false)
#4 /var/www/magazziniambrosi/html/includes/src/Varien_Cache_Core.php(145): Zend_Cache_Core->save('a:2:{i:0;a:7:{s...', 'APP_4E4ABDD8DC0...', Array, false, 8)
#5 /var/www/magazziniambrosi/html/includes/src/Mage_Core_Model_Cache.php(403): Varien_Cache_Core->save('a:2:{i:0;a:7:{s...', 'APP_4E4ABDD8DC0...', Array, false)
#6 /var/www/magazziniambrosi/html/includes/src/__default.php(22142): Mage_Core_Model_Cache->save('a:2:{i:0;a:7:{s...', 'app_4e4abdd8dc0...', Array, false)
#7 /var/www/magazziniambrosi/html/includes/src/__default.php(33441): Mage_Core_Model_App->saveCache('a:2:{i:0;a:7:{s...', 'app_4e4abdd8dc0...', Array)
#8 /var/www/magazziniambrosi/html/includes/src/__default.php(32645): Mage_Core_Model_Resource_Db_Collection_Abstract->_saveCache(Array, 'SELECT `main_ta...')
#9 /var/www/magazziniambrosi/html/includes/src/__default.php(33274): Varien_Data_Collection_Db->_fetchAll('SELECT `main_ta...', Array)
#10 /var/www/magazziniambrosi/html/includes/src/__default.php(32480): Mage_Core_Model_Resource_Db_Collection_Abstract->getData()
#11 /var/www/magazziniambrosi/html/includes/src/__default.php(33999): Varien_Data_Collection_Db->load(false, false)
#12 /var/www/magazziniambrosi/html/includes/src/__default.php(31844): Mage_Core_Model_Resource_Store_Collection->load()
#13 /var/www/magazziniambrosi/html/includes/src/__default.php(21611): Varien_Data_Collection->count()
#14 /var/www/magazziniambrosi/html/includes/src/__default.php(21453): Mage_Core_Model_App->_initStores()
#15 /var/www/magazziniambrosi/html/includes/src/__default.php(21336): Mage_Core_Model_App->_initCurrentStore('', 'store')
#16 /var/www/magazziniambrosi/html/app/Mage.php(684): Mage_Core_Model_App->run(Array)
#17 /var/www/magazziniambrosi/html/index.php(84): Mage::run('', 'store')
#18 {main}