I get this error to. I made some posts "Protected" and now I get this error when I'm accessing the protected posts not beeing logged in.

The second solution in this post should help (it's at the end of the post): http://forums.b2evolution.net/viewtopic.php?p=77969#77969.

Hello.

I encountered this exact same error yesterday after seeing that a couple of test posts I added to one blog were no longer showing up. I did a search and the missing post showed up. The error came when I clicked the link of that post in the search results. I also noticed that those missing posts weren't displaying in AdminUI.

Although I had also added new posts on another new blog, they were still showing up just fine. Both of those blogs included cross-posting from the demo blogs but only one of the two also utilized the 'Aggregate Blogs' feature.

Today, I recalled that I selected a couple of posts from a demo blog as previously mentioned above, and then decided later to test 'Aggregate Blogs' when included the blog from which those previous demo posts originated. That I believe was when 'all [h] broke loose.'

So the moral of the story is -- if you're going to 'Aggregate Blogs', make sure you hadn't previously used a post from those blogs via the cross-posting feature. The two are incompatible together. Remove the cross-post category first then aggregate.

Cheers!