gloups... avatars big bang bug ^^

hiya !

well, clicking on alternative upload I have :

There was an error uploading the file, please try again.
Warning: imagecopyresampled() expects parameter 2 to be resource, null given in /home/mgr/public_html/wp-content/plugins/avatars/avatars.php on line 507

Warning: imagecopyresampled() expects parameter 2 to be resource, null given in /home/mgr/public_html/wp-content/plugins/avatars/avatars.php on line 507

Warning: imagecopyresampled() expects parameter 2 to be resource, null given in /home/mgr/public_html/wp-content/plugins/avatars/avatars.php on line 507

Warning: imagecopyresampled() expects parameter 2 to be resource, null given in /home/mgr/public_html/wp-content/plugins/avatars/avatars.php on line 507

Warning: imagecopyresampled() expects parameter 2 to be resource, null given in /home/mgr/public_html/wp-content/plugins/avatars/avatars.php on line 507

Warning: unlink(/home/mgr/public_html/wp-content/uploads/avatars/blog/6ac/) [function.unlink]: Is a directory in /home/mgr/public_html/wp-content/plugins/avatars/avatars.php on line 1170

Warning: Cannot modify header information - headers already sent by (output started at /home/mgr/public_html/wp-content/plugins/avatars/avatars.php:472) in /home/mgr/public_html/wp-includes/pluggable.php on line 934