Appointments+ - Theme Conflict

I have a theme installed on a subdomain: TB-Hair Salon from a developer at I installed the Appointments+ plugin on that site and everything worked fine with one exception. I am unable to input name and email address into the boxes for making an appointment. No problem when I switch to the Twenty Eleven theme. Any idea what could cause that type of issue. I want to bring the issue to the theme's developer, but I also want to be able to give him any knowns incompatibilities that you have already uncovered. Anything you can supply would be helpful.