Avatars

hello I hae the following bug with avatars.
I'm pretty lost with this.
Thank you for your help.
Olivier

- avatars-3.4
After the installation reported:
Fatal error: Cannot redeclare wp_check_filetype() (previously declared in /home/unecerta/public_html/wp-includes/functions.php:2285) in /home/unecerta/public_html/wp-content/plugins/avatars-3.4/avatar.php on line 28
[not disabled]