Update (from v5.15.2) failed

Hi,
Plugin is updated in localhost, also in “testbed” domain few days ago but it is not updated in the “main” domain today, in the same server with the same file permission structures (Folders 755, Files 644).

Error message: “Update failed: The update cannot be installed because we will be unable to copy some files. This is usually due to inconsistent file permissions.”

Note: only below two files are changed from original.
1. /business-directory-plugin/templates/category.tpl.php
2. /business-directory-plugin/templates/single.tpl.php

I need your help to get the plugin updated.
Thanks and regards.