Plugin: Kathy Darling – Name your Price – Can not reach cart

Hi,
i use WooCommerce and the Name your Price Plugin.
Worked fine for a while, but now i can not reach the Cart if i set a minimum price.
If the minimum price is 0, then the product is added to cart, but the price is always 0. No matter what i enter in the value field.

You can give it a try with this product:
http://www.photobooth-deluxe.de/shop/allgemein/female-model-posing-guide/