Avatar Plugin – resides in different directory WPMUforJoomla

Hello, My custom wpmu component for Joomla resides in

/httpdocs/components/com_wpmu

below that directory things look normal for wpmu install

The rewrite rule in the install instructions is:

RewriteEngine on

RewriteRule ^(.*/)?avatar/(.*) wp-content/avatar.php?file=$2 [L]

I tried changing it to

RewriteEngine on

RewriteRule ^(.*/)?avatar/(.*) components/com_wpmu/wp-content/avatar.php?file=$2 [L]

When i try to upload the file i get error message

" NOT FOUND The requested URL /administrator/users.php was not found on this server."

Any help getting this plugin to work with my version of wpmu would be greately appreciated…wjwjr