It’s a conflict with your logo-slider plugin. We are both using a jQuery plugin called cycle to handle our testimonials. I recently updated to the latest version and unfortunately it won’t work if an older version is on the page and being called.
I will get in touch with the creator of it and see if something can be done. Version 1.3.3 was the version when I switched. If you jump back to 1.3.2 it should rotator again.