NextGen and BB-Gallery conflict (?)

I have NextGen installed and working and have uploaded many photos. I was using this as a site wide gallery and decided to let users have their own galleries so I added BB-Gallery. While activating this plug in the system blew up and returned a 500 System Server error. I can not get to my site at all without this error. It would seem to have been caused by the two plug ins not playing well together. I am now stuck and do not know how to resolve this. I tried restoring a backup but that did not work. I read about deleting a .htaccess file but cannot locate it. I would try to delete bb-gallery but cannot get to the WordPress admin panel. Any suggestions would be greatly appreciated. Thank you.

http://wordpress.org/plugins/nextgen-gallery/