Mimbo Theme Images Issues

I have no idea what happened, but the images stopped working for various themes that use timthumb.php. The latest is the Mimbo theme (previously the Chronicle theme) for my site at funkatopia.com. The images are showing fine on the posts themselves, but not on the home page or category pages.

I’ve tried;
1) re-uploading the new version of timthumb.php
2) Changing the script folder and timthumb.php file permissions to 777
3) temoporarily deactivating security programs thinking that may be the issue
4) and lastly I found a post for Mimbo Pro that said I should open each post and choose the image I want as the “featured image” and then it would show up. Problem is that for soem reason, there is no featured Image area (normally bottom right, but not there now). It’s not under the Edit Image area either, which is strange.

Any thoughts on what I’m missing?