Fatal error on Product Comparison Page

I have a fatal error on the Product Comparison Page, saying :

Fatal error: Call to a member function get_price_html() on a non-object in …/plugins/woocommerce-compare-products/classes/class-wc-compare-functions.php on line 427.

It worked earlier this morning, but after I tested the variation comparison, the error occured.
And now, even if I delete my variation, I still have the fatal error.
Once more, the Comparison button doesn’t show up anymore on my product page.

I tried to deactivate and reactivate the plugin, but that didn’t solve the problem.

http://wordpress.org/plugins/woocommerce-compare-products/