Not found on a massive ammount of pages in google all of a sudden

In a few days google webmaster tools say not found for over 1000 pages on the site but when I click the links the pages work.
What could the problem be, this has occured since I installed vBSEO, used to have arround 40 not founds.

What is an example URL?

Here is one example that google says not found but when click it in webmaster tools I get to the page.
zatzy racing community - Racebränsle
( here is how the link looks at google http://www.zatzy.com/forum/showthrea...threadid=41046 )

Looking at it closer now I see that most of the errors i related to Photopost (actually not found), http://www.zatzy.com/photopost/showg...2/ppuser/53772

Is this related to vBSEO or is it a coincidence that all photopost likns have broken at the same time as it was installed?

Looking at it closer now I see that most of the errors i related to Photopost (actually not found)

Please try to create .htaccess file in photopost folder with one line:

Code:

RewriteEngine off

Originally Posted by Oleg Ignatiuk

Please try to create .htaccess file in photopost folder with one line:

Code:

RewriteEngine off

That worked, thanks!