Don't use error suppression on is_dir(), file_exists()
diff --git a/system/core/Output.php b/system/core/Output.php
index d494d00..7a35b02 100644
--- a/system/core/Output.php
+++ b/system/core/Output.php
@@ -639,7 +639,7 @@
 		$uri =	$CFG->item('base_url').$CFG->item('index_page').$URI->uri_string;
 		$filepath = $cache_path.md5($uri);
 
-		if ( ! @file_exists($filepath) OR ! $fp = @fopen($filepath, FOPEN_READ))
+		if ( ! file_exists($filepath) OR ! $fp = @fopen($filepath, FOPEN_READ))
 		{
 			return FALSE;
 		}