This error in your Sharepoint installation means that your search server is not configured. Follow these steps to resolve this error:

First of all verify that your "Search Service" has been started in the Operations part of Central Administration and in Control Panel -> Administrative Tools -> Services as well.

Then:

Go to
 Central Admin
 Applicaton Management tab
 SharePoint Web Application Management heading | Content databases
 Ensure your web application is the one selected
 Select your content database name
 Under Search Server - select your server
OK 

Hope this helps!