I have installed back to stock notification and request restock add on in my website. back to stock notification add on was working perfectly ok before request restock was installed.

After Request restock addon installation I get the error message as

Fatal error: Cannot redeclare process_product_name() (previously declared in /home6/public_html/.....admin/includes/functions/extra_functions/request_restock.php:113) in /public_html/admin/includes/functions/back_in_stock_notifications_functions.php on line 370

Can anyone please help?
thanks