The Avatar Plugin Hosed up my BP site

Hi, well, I read the pitch on the Avatar plugin and decided that sounded good.

Now I have a problem.

I'm building a MU BP site and activated the Avatar plugin.

Now any page I attempt to go to gives me this error instead.
Fatal error: Class 'WA_Widget_Avatars' not found in /home4/sentina1/public_html/theheritagesource.com/wp-includes/widgets.php on line 413

I can't do anything at all now.

So, I went to the wp-includes file and looked at it with edit to see it I could find the plugin and delete it. Nope! I was unable to find it. I thought I could inactivate it or?

I need help to fix this please. What should I do?
I can't get to the plugin on the site to deactivate it there of course or I would.

Thank you, Patrick