typo fix
diff --git a/system/libraries/Output.php b/system/libraries/Output.php
index 743228e..756d4b4 100644
--- a/system/libraries/Output.php
+++ b/system/libraries/Output.php
@@ -275,7 +275,7 @@
 

 		if ( ! $fp = @fopen($cache_path, 'wb'))

 		{

-			log_message('error', "Unable to write ache file: ".$cache_path);

+			log_message('error', "Unable to write cache file: ".$cache_path);

 			return;

 		}