[Mediawiki-l] error with wikifeeds extension

[city wiki]

The wiki I manage has extension wikifeeeds and randomly shows this error

exception 'RuntimeException' with message
'DirectoryIterator::__construct(/nfsn/content/ds-x/public/tmp/)
[function.DirectoryIterator---construct]: failed to open dir: No such
file or directory' in
/var/www/html/w/extensions/SpecialWikiFeeds.php:820 Stack trace: #0
/var/www/html/w/extensions/SpecialWikiFeeds.php(820):
DirectoryIterator->__construct('/nfsn/content/d...')
#1 /var/www/html/w/extensions/SpecialWikiFeeds.php(797):
SpecialWikiFeeds->_getCacheFiles()
#2 /var/www/html/w/extensions/SpecialWikiFeeds.php(188):
SpecialWikiFeeds->_cachePrune()
#3 /var/www/html/w/extensions/SpecialWikiFeeds.php(907):
SpecialWikiFeeds->__construct()
#4 [internal function]: wfWikiFeeds()
#5 /var/www/html/w/includes/Setup.php(300): call_user_func('wfWikiFeeds')
#6 /var/www/html/w/includes/WebStart.php(112):
require_once('/var/www/html/w...')
#7 /var/www/html/w/index.php(40): require_once('/var/www/html/w...') #8 {main}



¿¿any ideas??  thanks!