People Search Settings / Page 404 error for People Search
Make sure you have set the following properly:
1. In the Shared Services Provider –> Search Settings –> Content Sources –> <Your Search Site List> –> sps3://<sitename> has been specified. Most likely you have removed this from the list thinking it is not useful!
2. Make sure you have a Search Center site setup. If this is not available, create one using:
Site Settings –> Create Site –> Enterprise –> Search Center / Search Center with Tabs. (for e.g. let this be http://yoursite.com/Search)
3. Go to Site Settings (Site Collection Administration Settings) –> Search Settings –> Use Custom Scope –> http://yoursite.com/Search
Now you should start seeing your results!