Index: wp-admin/edit-form-advanced.php
===================================================================
--- wp-admin/edit-form-advanced.php	(revision 23992)
+++ wp-admin/edit-form-advanced.php	(working copy)
@@ -463,28 +463,31 @@
 	<td id="wp-word-count"><?php printf( __( 'Word count: %s' ), '<span class="word-count">0</span>' ); ?></td>
 	<td class="autosave-info">
 	<span class="autosave-message">&nbsp;</span>
-<?php
+	<span id="last-edit">
+	<?php
+
 	if ( 'auto-draft' != $post->post_status ) {
-		echo '<span id="last-edit">';
-		if ( $last_id = get_post_meta($post_ID, '_edit_last', true) ) {
-			$last_user = get_userdata($last_id);
-			printf(__('Last edited by %1$s on %2$s at %3$s'), esc_html( $last_user->display_name ), mysql2date(get_option('date_format'), $post->post_modified), mysql2date(get_option('time_format'), $post->post_modified));
-		} else {
-			printf(__('Last edited on %1$s at %2$s'), mysql2date(get_option('date_format'), $post->post_modified), mysql2date(get_option('time_format'), $post->post_modified));
-		}
-		echo '</span>';
-	} ?>
+		if ( ( $last_id = get_post_meta( $post_ID, '_edit_last', true ) ) && ( $last_user = get_userdata( $last_id ) ) )
+			printf( __('Last edited by %1$s on %2$s at %3$s'), esc_html( $last_user->display_name ), mysql2date( get_option('date_format'), $post->post_modified ), mysql2date( get_option('time_format'), $post->post_modified ) );
+		else
+			printf( __('Last edited on %1$s at %2$s'), mysql2date( get_option('date_format'), $post->post_modified ), mysql2date( get_option('time_format'), $post->post_modified ) );
+	}
+
+	?>
+	</span>
 	</td>
 </tr></tbody></table>
 
 </div>
-<?php }
+<?php
+}
 
 if ( has_action( 'edit_form_after_editor' ) ) {
 	echo '<div class="edit-form-section">';
 	do_action( 'edit_form_after_editor' );
 	echo '</div>';
 }
+
 ?>
 </div><!-- /post-body-content -->
 
Index: wp-includes/comment-template.php
===================================================================
--- wp-includes/comment-template.php	(revision 23992)
+++ wp-includes/comment-template.php	(working copy)
@@ -22,17 +22,17 @@
  */
 function get_comment_author( $comment_ID = 0 ) {
 	$comment = get_comment( $comment_ID );
-	if ( empty($comment->comment_author) ) {
-		if (!empty($comment->user_id)){
-			$user=get_userdata($comment->user_id);
-			$author=$user->user_login;
-		} else {
+
+	if ( empty( $comment->comment_author ) ) {
+		if ( ! empty( $comment->user_id ) && ( $user = get_userdata( $comment->user_id ) ) )
+			$author = $user->display_name;
+		else
 			$author = __('Anonymous');
-		}
 	} else {
 		$author = $comment->comment_author;
 	}
-	return apply_filters('get_comment_author', $author);
+
+	return apply_filters( 'get_comment_author', $author );
 }
 
 /**