Use Categories Path for Product URLs not working

Question

I have set "Use Categories Path for Product URLs" to "No", but still on frontend I am seeing product urls with category paths.
Checked attribute value on store level also, and it is set to "No" as required. I have performed re-indexation and cleared cahe (both Magento and browsers).
I am using Magento 1.4.2.0

UPDATE
When I am looking at product collection, it is not having any attirube named "request_path" instead it is showing "url_path".

Please let me know if it was a default magento bug in this version or I am missing something.
Any help will be appreciated.