Hi, I've broken something and have absolutely no idea what, or how to fix it. Here's all the information I can think of. I'd really appreciate some help if anyone has some input.
I'm building a simple theme for a site athttp://startensei.com and at some point the "Add to cart" buttons stopped working.
I updated both Concrete5 and CoreCommerce on Friday, and I know that it was still working then as I double checked to make sure I wouldn't need to roll back.
The add to cart buttons work in the Plain Yoghurt theme, so I know the problem is with my theme, rather than anything CoreCommerce related, but as far as I'm aware there have been no changes that should affect CoreCommerce.
I have a very basic knowledge of php, and virtually nothing in javascript, so I'm having a pretty hard time troubleshooting where in my theme the problem exists.
Chrome console gives me this post when I click the add button:

POSThttp://startensei.com/index.php/cart/update/... 404 (Not Found)
f.support.ajax.f.ajaxTransport.send jquery.js:4
f.extend.ajax jquery.js:4
$.fn.ajaxSubmit jquery.form.js:177
$.fn.ajaxForm.ajaxFormUnbind.bind.bind.target jquery.form.js:594
f.event.dispatch jquery.js:3
f.event.add.h.handle.i jquery.js:3

Any help would be greatly appreciated. If there's anything I've missed, just let me know.

Thanks in advance,
Ryan