Warning: call_user_func_array() [function.call-user-func-array] error

I’m getting this error in the post excerpts on my front page:

Warning: call_user_func_array() [function.call-user-func-array]: First argument is expected to be a valid callback, ‘new_excerpt_more’ was given in /home/content/94/11264694/html/wp-includes/plugin.php on line 173

It seems that it started after I installed Floating Social Media Links and configured it. I deactivated it, but that didn’t fix the problem. I deleted all files associated with that plugin, but that didn’t work either. I’ve deactivated all my plugins several times but it doesn’t fix it. I renamed my plugins folder “plugins.hold” but that didn’t fix it either.

I changed the theme to Twenty Twelve and I don’t get the excerpt error. So the problem has something to do with the Soundboard theme I’m using, but I didn’t have this problem before the Floating Social plugin and the problem isn’t solved by deleting the Floating Social plugin files.

I’m not sure what to do. Here’s the site – scroll down toward the bottom under Headlines to see the error:

http://rallycross360.com/

Please share any ideas you might have about this. Thanks!

Kristin