Increase in not found errors

-- HikaShop version -- : 2.3.3
-- Joomla version -- : 2.5.27
-- PHP version -- : 5.3.29
-- Error-message(debug-mod must be tuned on) -- : Google detected a significant increase in the number of URLs that return a 404 (Page Not Found) error. Investigating these errors and fixing them where appropriate ensures that Google can successfully crawl your site's pages.

Hi
I got this message from Google Webmasters Tools : Increase in not found errors
Checking the urls from the list I saw that all of them are products assigned in unpublished menuitems and that the specific urls are from the contact for more information of the product.

How can I disallow crawling at the unpublished items ?

Hello,
If you are using a SEF module / SEF options, can you disable it and try it again so that we can know if it's coming from it ?

The only third party extentions intalled are a FaceBook like box and an accordion module

Hi,

Well, the 404 error exactly indicates that the URLs cannot be crawled/accessed anymore. Since Google already knows that the URL existed before, when it looks again at it in order to see if anything changed, it sees that it is not available anymore, and won't crawl it again. And since that happened a lot, you got that notification.
So it looks normal and not much we can avoid.