load config files from environment specific locations in core classes, helpers and libraries
diff --git a/system/helpers/file_helper.php b/system/helpers/file_helper.php
index 9518e48..fb074e0 100644
--- a/system/helpers/file_helper.php
+++ b/system/helpers/file_helper.php
@@ -352,7 +352,16 @@
 
 		if ( ! is_array($mimes))
 		{
-			if ( ! require_once(APPPATH.'config/mimes.php'))
+			if (file_exists(APPPATH.'config/'.ENVIRONMENT.'/mimes'.EXT))
+			{
+			    @include(APPPATH.'config/'.ENVIRONMENT.'/mimes'.EXT);
+			}
+			else
+			{
+				@include(APPPATH.'config/mimes'.EXT);
+			}
+			
+			if ( ! is_array($mimes))
 			{
 				return FALSE;
 			}