diff --git a/system/libraries/Upload.php b/system/libraries/Upload.php
index f804dce..33ee947 100644
--- a/system/libraries/Upload.php
+++ b/system/libraries/Upload.php
@@ -512,7 +512,7 @@
 	 */	
 	function is_allowed_filetype()
 	{
-		if (count($this->allowed_types) == 0)
+		if (count($this->allowed_types) == 0 || ! is_array($this->allowed_types))
 		{
 			$this->set_error('upload_no_file_types');
 			return FALSE;