I tried to login to my admin this evening and got this message;

Fatal error: Cannot redeclare zen_get_artists_url() (previously declared in /home/therscom/public_html/store/admin/includes/functions/extra_functions/product_music_functions.php:25) in /home/therscom/public_html/store/admin/includes/functions/extra_functions/product_music_functions.php.bac on line 25

Can anyone help me with this? THe store is alright, I just want to add some products.