Your search cannot be completed because this site is not assigned to an indexer. Contact your administrator for more information.

Mar 21, 2008 at 12:45 AM
Tried to use this on http://www.wssdemo.com/blog
The blog site is just a sub site of a MOSS top level collaboration site. There is also a search center sub site which works fine for all sub sites in the site collection including the blog site.
Mar 22, 2008 at 7:55 PM
The Windows SharePoint Services search service must be running on the farm (solution doesn't use Office SharePoint Server search).
You need to assign an indexer to your content database, jopx has a quick write up here, but then everything should come to life: http://jopx.blogspot.com/2007/08/solving-sharepoint-site-not-assigned-to.html

If you have MOSS, this will mean doubling up on indexing so you might want to have your blog in a dedicated site collection/content db.