Some customers are not seeing the Add to Cart button on variable products.
I see it in Safari, Firefox, and Chrome (can't check IE).
Some background on this thread -- http://wordpress.org/support/topic/variable-product-add-to-cart-button?replies=9
Once I removed the radio button plugin, the error on Firebug resolved, but customers still can't see the button.
All plugins and themes are up-to-date. It happens with Twenty Ten & Twenty Twelve themes.
No idea where to go from here. I'm not a code person, but I really need to fix this!