Index: includes/Title.php
===================================================================
--- includes/Title.php	(revision 17246)
+++ includes/Title.php	(working copy)
@@ -1551,6 +1551,16 @@
 			return false;
 		}
 
+		/**
+		 * Pages whose titles start with / can confuse webservers
+		 * and proxies. They can be unreachable with the pretty
+		 * URLs. Forbid them explicitly.
+		*/
+		if ( strpos( $r, '/') === 0 )
+		{
+			return false;
+		} 
+
 		# We shouldn't need to query the DB for the size.
 		#$maxSize = $dbr->textFieldSize( 'page', 'page_title' );
 		if ( strlen( $r ) > 255 ) {