Index: wp-includes/pluggable.php
===================================================================
--- wp-includes/pluggable.php	(revision 21655)
+++ wp-includes/pluggable.php	(working copy)
@@ -1060,9 +1060,12 @@
 		if ( '' != $comment->comment_author_email )
 			$reply_to = "Reply-To: $comment->comment_author_email";
 	} else {
-		$from = "From: \"$comment->comment_author\" <$wp_email>";
-		if ( '' != $comment->comment_author_email )
-			$reply_to = "Reply-To: \"$comment->comment_author_email\" <$comment->comment_author_email>";
+		if ( '' != $comment->comment_author_email ) {
+			$from = "From: \"$comment->comment_author\" <$comment->comment_author_email>";
+			$reply_to = "Reply-To: \"$comment->comment_author\" <$comment->comment_author_email>";
+		} else {
+			$from = "From: \"$comment->comment_author\" <$wp_email>";
+		}
 	}
 
 	$message_headers = "$from\n"