Index: ours/phpbb/includes/functions_messenger.php
===================================================================
--- ours/phpbb/includes/functions_messenger.php	(revision 231)
+++ ours/phpbb/includes/functions_messenger.php	(working copy)
@@ -653,9 +653,15 @@
 		// on the assumption that the winning process created it
 		if (!$lock_fp && $mode == 'wb')
 		{
-			$lock_fp = @fopen($this->cache_file . '.lock', 'rb');
+			// Assign to $mode for the check in chmod below
+			$mode = 'rb';
+			$lock_fp = @fopen($this->cache_file . '.lock', $mode);
 		}
-		@chmod($this->cache_file . '.lock', 0666);
+		if ($lock_fp && $mode == 'wb')
+		{
+			// Only need to set mode when the lock file is written
+			@chmod($this->cache_file . '.lock', 0666);
+		}
 		if ($lock_fp)
 		{
 			@flock($lock_fp, LOCK_EX);