Please help - urgent

I have just become a member. I have my own site not in wordpress.org. I have my buddypress installed working with default template. I have downloaded buddysocial theme. I have activated it and then tried to configure it. I got the message below.when I try http://www.tangosfer.net/tangosfer/wp-admin/

Fatal error: Cannot redeclare bp_dtheme_ajax_querystring() (previously declared in /home6/tangosfe/public_html/tangosfer/wp-content/plugins/buddypress/bp-themes/bp-default/_inc/ajax.php:20) in /home6/tangosfe/public_html/tangosfer/wp-content/themes/buddypresssocial/bp-social/_inc/ajax.php on line 63

my site is

http://www.tangosfer.net/tangosfer/ It shows the old theme since I cannot load yours.

Regards,
Aydogan