When components call cacheClean it calls the storage clean method regard...

...less of whether the cache is enabled or disabled.  This will cause problems if the caching mechanism it is using are not configured properly[since they aren't being used!].  Joomla defaults to the first enabled caching method it finds, regardless of whether it is configured properly - thus throwing errors and warnings when cleaning cache.

This hack will switch to file caching if caching is disabled to avoid these issues.