Solution:1
It happened to me too, and this is the second time!
If you don’t have time to discover why, but you want to keep it working, just rename, or delete your /cache folder; then, create a brand new /cache folder, set permissions to 777, and it will work again.
Solution:2
I found that the cache folder this is referring to is the one within the same folder as timthumb.php – find that file and the related cache folder and give the cache folder 777 permissions.
Solution:3
if you are on a linux based server,
first find the FILE_CACHE_DIRECTORY from the config file by (ex. in linux server open the file in vi commond)
vi /system/web/esupu/wp-content/themes/gadgetry-parent/framework/timthumb/timthumb-config.php
it could be like
define(‘FILE_CACHE_DIRECTORY’, ‘../../cache/’);
SO we change the cache folder ownership to user “www-data” which is the default user for Apache web server which runs this php codes,
sudo chown -hR www-data:www-data /system/web/esupu/wp-content/themes/gadgetry-parent/cache/
also, now better check if folder can be writable too (chmod permissions to 777)