Avatars not uploading

Hi, I am using the latest version of both WPMU and the Avatars plugin. I get no image uploaded when I click upload (crop shows as a broken image). No images show up in my /wp-content/avatars/user/c4c directory as well. I have quadruple checked the .htaccess, it currently reads as follows:

#uploaded files
RewriteRule ^(.*/)?files/$ index.php [L]
RewriteCond %{REQUEST_URI} !.*wp-content/plugins.*
RewriteRule ^(.*/)?files/(.*) wp-content/blogs.php?file=$2 [L]
RewriteRule ^(.*/)?avatar/(.*) wp-content/avatar.php?file=$2 [L]
RewriteRule ^(.*/)?sitemap.xml wp-content/sitemap.php [L]

I have quadruple checked the /wp-content/avatars directory and associated subdirectories for chmod 777, yet my avatars are not being uploaded. Any thoughts?

Thanks in advance,
Louis