Hi,
I had the same problem and managed to solve it.
The reason for this was simple, timthumb.php script was blocked by a mod_security rule on my host server. I have asked them to whitelist my domain (disabled sec rules) and the site appears to be working now.
My domain is hosted by Hostgator, they fixed the problem in 5 min.
It’s worth a try to contact your host provider and ckeck it out.
Hope it helped 🙂
