timthumb error Could not get a lock for writing.

Hi,

I’ve worked before with timthumb and had no problems before, but for this version the image is not showing its just the link of the URL. The URL of my site is: http://www.everify.com/resources/ and you can see the problem under “Discover Who’s Calling with a Reverse Phone Number Lookup”. And when I go to this URL: http://www.everify.com/resources/wp-content/themes/eVerify/scripts/timthumb.php?src=http://www.everify.com/resources/wp-content/uploads/2012/02/Reverse-Phone-Search.jpg&h=150&w=150 I see the following error: Could not get a lock for writing.

But my cache folder chmod settings are set to 777 and they were 755 before and I got the same error.

Can someone suggest me a solution?
Thanks

http://wordpress.org/extend/plugins/timthumb/