After upgrading from SharePoint 2007 or moving SharePoint 2010 to another server, you need to update broked links
in Navigation Bars (Top Navigation Bar or Quick Lanch Navigation Bar). I found solution for this problem in SharePoint 2007
Replacing Navigation URLs Using STSADM, this solution use stsadm command for update Navigation LInks.
I upgrade this code for SharePoint 2010 and build Windows Application, that help to update or replace links inside
Navigation Bars. You can update navigation link in three level: "webapplication", "site", "web"
Here I put C# Source for Update Navigation Bar Project: ReplaceNavigationSource.zip
If you want only binary executable file you can download it here: ReplaceNavigationUrl.zip