Error after update – Site is crashing!

I get this error after update.

Warning: require_once(/var/www/gate36.dk/public_html/wp-content/plugins/wc-return-product//includes/wc_functions.php) [function.require-once]: failed to open stream: No such file or directory in /var/www/gate36.dk/public_html/wp-content/plugins/wc-return-product/wc_return_product.php on line 25

Fatal error: require_once() [function.require]: Failed opening required ‘/var/www/gate36.dk/public_html/wp-content/plugins/wc-return-product//includes/wc_functions.php’ (include_path=’.’) in /var/www/gate36.dk/public_html/wp-content/plugins/wc-return-product/wc_return_product.php on line 25

https://www.ads-software.com/plugins/wc-return-product/