Index: wp-includes/query.php
===================================================================
--- wp-includes/query.php	(revision 18633)
+++ wp-includes/query.php	(working copy)
@@ -1552,7 +1552,7 @@
 			if ( '' != $qv['author_name'] )
 				$this->is_author = true;
 
-			if ( !empty( $qv['post_type'] ) && ! is_array( $qv['post_type'] ) ) {
+			if ( ! empty( $qv['post_type'] ) && ! is_array( $qv['post_type'] ) && ! $this->is_search ) {
 				$post_type_obj = get_post_type_object( $qv['post_type'] );
 				if ( ! empty( $post_type_obj->has_archive ) )
 					$this->is_post_type_archive = true;