Cannot Update Quantity - Jquery?

slsonline.us/courses/ropes-knots
I have installed JQuery Easy to see if this would fix the problem and it has not. I read the forums on here and some said Jquery Easy worked for them. I am not savvy enough to show conflicts in firebug yet.

I cannot update quantities in the cart and nothing happens when I click checkout

Any idea?

Hi David

As replied via email, this issue happens because you have Prevent Duplicate Registration config option set to Yes

Set it to No will help solving the issue

Tuan