Creating the nicename with a space in it breaks %author% links. It is my understanding that the nicename should be passed through sanitize_title first. Which will convert the space to a dash.
See http://wordpress.org/support/topic/plugin-shibboleth-username-at-risk-of-breaking-permalinks-with-author
http://codex.wordpress.org/Function_Reference/sanitize_title
I haven't finished testing yet but I changed to code to
$userData = array(
'user_pass' => microtime(),
'user_login' => $userinfo[0][samaccountname][0],
'user_nicename' => sanitize_title($userinfo[0][givenname][0] .' '.$userinfo[0][sn][0]),
'user_email' => $userinfo[0][mail][0],
'display_name' => $userinfo[0][givenname][0] .' '.$userinfo[0][sn][0],
'first_name' => $userinfo[0][givenname][0],
'last_name' => $userinfo[0][sn][0],
'role' => strtolower(get_option('simpleldap_account_type'))
);