Same thing here. I have WooCommerce 2.0.18 and Piggy 2.0.1 and on my main piggy page i get some script errors and then if i try to use the password it doesnt accept it. If i change it so it isnt using woocommerce and is just none, the password works and the script errors disappear.
Here is the error, some of it gets cut off on the page:
Warning: implode() [function.implode]: Invalid arguments passed in /home/content/77/11894477/html/wp-content/plugins/piggy-lite/include/helpers/woo-commerce.php on line 35
Warning: implode() [function.implode]: Invalid arguments passed in /home/content/77/11894477/html/