Have redone your page and supporting files, they just need to be placed in the same folders as your originals (you should back up your existing files and folders first!).
It was a bit of a nightmare - there was multiple duplicated blocks of code, (a problem with CSSFormBuilder) and when it was finally finished, the captcha didn't validate (again). There was also no server-side validation - did you remove it?
I redid the form - also the server-side validation - and it seems to work fine now. The Captcha field is the last to validate, you will only be able to truly test it once the other fields have been filled in correctly.
Hope it goes well.
For some reason the zip won't attach; - you can download it HERE