In your Joomla backend, please open the plugin Joomla Admin Menu > System > Manage > Plugins > FileSystem - Local, and revise the settings. Make sure that the listed folders actually exist. For a test I recommend configure the plugin so that only the the folder images in your Joomla site's root is listed.
Important: Removing an entry for a folder in this plugin does not delete the folder or otherwise touch its content.
Regardless of whether or not you have changed anything — click on "Save" or "Save & Close". Then try again what failed.