URGENT HELP NEEDED

I was previously using the 'Cool Theme 1.0' and changed it to the 'Facebook_Theme' but now my website has crashed and is showing the following;

Fatal error: Cannot redeclare facebook_theme_init() (previously declared in /hermes/bosnaweb10a/b610/ipg.mumsmaternalmagiccou/dolphin/mod/cool_theme/start.php:7) in /hermes/bosnaweb10a/b610/ipg.mumsmaternalmagiccou/dolphin/mod/facebook_theme/start.php on line 67

What can I do to fix this? Incidentally, I renamed the 'Cool Theme 1.0' file in the /mod directory to 'Facebook_Theme' thinking it might sort it out but clearly not!

Please someone help!! :-/