Can’t see website or access wordpress anything

Hi, I was d eactivating the theme switche in under wp-plugins and got this message:

Hi, I was deactvating the them switcher plugin under wp-pkugins and got this message:

<b>Fatal error</b>: Cannot redeclare ts_set_theme_cookie() (previously declared in /home/heroindi/public_html/maryblackchurch/wp-content/plugins/theme-switcher.php:31) in <b>/home/heroindi/public_html/maryblackchurch/wp-content/plugins/theme_switcher.php</b> on line <b>30</b><br /

I know I’m supposed to rename a folder or something but can’t recall exactly what to do.

Thanks.