For these who got problems with gravatars replace code in author-exposed.php around line 35
$gravatar = 'http://www.gravatar.com/avatar.php?gravatar_id=' .md5($mail);
with one that suggested on gravatar.com support site for php
$gravatar ="http://www.gravatar.com/avatar/" . md5( strtolower( trim( $mail ) ) ) . "?d=" . urlencode( $default ) . "&s=" . $size;