Some people have recently reported getting timeout errors when performing searching that uses the SQL Server full text search. This may be a knowledge base search, or a job search.
Microsoft have a knowledge base article that address this issue for specific environments - "You may experience a 45-second delay when you run a full-text query in an instance of SQL Server 2005 that is running on a server without Internet access"
http://support.microsoft.com/kb/915850/en-us