load config files from environment specific locations in core classes, helpers and libraries
diff --git a/system/helpers/download_helper.php b/system/helpers/download_helper.php
index 6cecd0d..a851e3c 100644
--- a/system/helpers/download_helper.php
+++ b/system/helpers/download_helper.php
@@ -58,7 +58,14 @@
 		$extension = end($x);
 
 		// Load the mime types
-		@include(APPPATH.'config/mimes'.EXT);
+		if (file_exists(APPPATH.'config/'.ENVIRONMENT.'/mimes'.EXT))
+		{
+		    @include(APPPATH.'config/'.ENVIRONMENT.'/mimes'.EXT);
+		}
+		else
+		{
+			@include(APPPATH.'config/mimes'.EXT);
+		}
 
 		// Set a default mime if we can't find it
 		if ( ! isset($mimes[$extension]))