Unable to activate Avatars 3.1 with WPMU 2.6.1


I'm attempting to install avatars 3.1 plugin on my wpmu 2.6.1 site
Not sure what information I should include in this post
I seem to be having issues with avatars.php and pluggable.php

"Plugin could not be activated because it triggered a fatal error.

Fatal error: Cannot redeclare get_avatar() (previously declared in /homepages/26/d241578522/htdocs/curse/test/wp-includes/pluggable.php:1337) in /homepages/26/d241578522/htdocs/curse/test/wp-content/plugins/avatars.php on line 145"

Any suggestions would be appreciated