Index: wp-includes/class-wp.php
===================================================================
--- wp-includes/class-wp.php	(revision 19209)
+++ wp-includes/class-wp.php	(working copy)
@@ -184,8 +184,7 @@
 			$this->request = $request;
 
 			// Look for matches.
-			$request_match = $request;
-			if ( empty( $req_uri ) ) {
+			if ( empty( $req_uri ) && empty( $request ) ) {
 				// An empty request could only match against ^$ regex
 				if ( isset( $rewrite['$'] ) ) {
 					$this->matched_rule = '$';
@@ -197,7 +196,10 @@
 					// If the requesting file is the anchor of the match, prepend it to the path info.
 					if ( ! empty($req_uri) && strpos($match, $req_uri) === 0 && $req_uri != $request )
 						$request_match = $req_uri . '/' . $request;
+					else
+						$request_match = $request;
 
+
 					if ( preg_match("#^$match#", $request_match, $matches) ||
 						preg_match("#^$match#", urldecode($request_match), $matches) ) {