WordPress theme or plugin TimThumb error – causes and fixes

Solution 1:
I experienced this issue as well. If you don’t have time to investigate the root cause but need a quick fix:

• Rename or delete your existing /cache folder.
• Create a new /cache folder.
• Set its permissions to 777.

After this, your system should start working properly again.

Solution 2:
The cache folder in question is located in the same directory as timthumb.php.

• Locate timthumb.php in your installation.
• Find the associated cache folder in the same directory.
• Set the permissions of the cache folder to 777.

This should resolve the caching issue.