Consider the following scenario:
You enable publishing on a Microsoft SharePoint Server 2010 server.
You create a new subsite in the root of a site collection, and then the subsite is displayed in the Home Page navigation bar.
You delete the subsite.
In this scenario, the subsite is still displayed in the Home Page navigation bar. When you update the Home Page, the word Error is displayed in the navigation bar.
To work around this issue, apply one of the following methods:
Refresh the Home Page again.
Reduce the permissions of most site collection administrators.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.