Matched root_path's slashes with the name being replaced
diff --git a/system/libraries/Zip.php b/system/libraries/Zip.php
index f2f1714..3e98ac5 100644
--- a/system/libraries/Zip.php
+++ b/system/libraries/Zip.php
@@ -352,7 +352,7 @@
 		// Set the original directory root for child dir's to use as relative
 		if ($root_path === NULL)
 		{
-			$root_path = dirname($path).DIRECTORY_SEPARATOR;
+			$root_path = str_replace(array('\\', '/'), DIRECTORY_SEPARATOR, dirname($path)).DIRECTORY_SEPARATOR;
 		}
 
 		while (FALSE !== ($file = readdir($fp)))