Product variant not available when adding product

-- url of the page with the problem -- : compostwerks.com
-- HikaShop version -- : 2.6.0
-- Joomla version -- : 3.4.4
-- PHP version -- : 5.3
-- Browser(s) name and version -- : Internet Explorer 11
-- Error-message(debug-mod must be tuned on) -- : Product variant not available when adding product to cart.

I found a bug in that when you add variants to your product, you have to click on the price and change the price from 0 to 0.00 in order for the option to be available when the variant price is 0. The price then shows up a $0.00 instead of a blank field price when you save it.