elliot.b on "woocommerce add-to-cart buttons not appearing"

http://wareofthedog.com/shop/ware/stripe-sweater/

check out this page, the add-to-cart button is supposed to appear, instead all I get is this JS error:
Uncaught TypeError: Cannot read property '154' of undefined,
add-to-cart-variation.min.js?ver=2.0.13:3

Searching around, this seems to be a pretty common issue with many different solutions/causes.

I have narrowed it down to a problem with this site's theme, as the add-to-cart buttons in twenty-ten, and other default themes, turning off plugins doesn't help either.

I do not usually work with Wordpress, and I did not write the theme, can someone help me understand how this "hooks" business works in woothemes?

Here's my content-single-product.php, the code has what looks like the atc button's functions commented and "hooked"

* @hooked woocommerce_template_single_add_to_cart - 30,

Do I have to make a change to the following code in woocommerce-hooks.php?

/**
	 * Product Add to cart
	 *
	 * @see woocommerce_template_single_add_to_cart()
	 * @see woocommerce_simple_add_to_cart()
	 * @see woocommerce_grouped_add_to_cart()
	 * @see woocommerce_variable_add_to_cart()
	 * @see woocommerce_external_add_to_cart()
	 */
	add_action( 'woocommerce_single_product_summary', 'woocommerce_template_single_add_to_cart', 30 );
	add_action( 'woocommerce_simple_add_to_cart', 'woocommerce_simple_add_to_cart', 30 );
	add_action( 'woocommerce_grouped_add_to_cart', 'woocommerce_grouped_add_to_cart', 30 );
	add_action( 'woocommerce_variable_add_to_cart', 'woocommerce_variable_add_to_cart', 30 );
	add_action( 'woocommerce_external_add_to_cart', 'woocommerce_external_add_to_cart', 30 );

or is the a problem with add-to-cart-variation.min.js?