I can't seem to activate the Pro Plugin, when I try I just

HI

I can't seem to activate the Pro Plugin, when I try I just get this message :

Fatal error: Cannot redeclare wp_smush_rating_message() (previously declared in /home/wp_dgujym/sharonsantoni.com/wp-content/plugins/wp-smushit/wp-smush.php:73) in /home/wp_dgujym/sharonsantoni.com/wp-content/plugins/wp-smush-pro/wp-smush.php on line 88

any help please?

thanks

Sharon