Index: wp-includes/rewrite.php
===================================================================
--- wp-includes/rewrite.php	(revision 6539)
+++ wp-includes/rewrite.php	(working copy)
@@ -721,10 +721,10 @@
 					$subfeedquery = $subquery . '&feed=' . $this->preg_index(2);
 
 					//do endpoints for attachments
-					if ($endpoint) { foreach ($ep_query_append as $regex => $ep) {
+					if ($endpoints) { foreach ($ep_query_append as $regex => $ep) {
 						if ($ep[0] & EP_ATTACHMENT) {
-							$rewrite[$sub1 . $regex] = $subquery . '?' . $ep[1] . $this->preg_index(2);
-							$rewrite[$sub2 . $regex] = $subquery . '?' . $ep[1] . $this->preg_index(2);
+							$rewrite[$sub1 . $regex] = $subquery . $ep[1] . $this->preg_index(2);
+							$rewrite[$sub2 . $regex] = $subquery . $ep[1] . $this->preg_index(2);
 						}
 					} }