Error: this site is not assigned to an indexer

I was writing a new web part to search Taxonomies (Managed metadata) in SharePoint 2010. During testing I got an error when using the class FullTextSqlQuery “Microsoft.SharePoint.SPException: Your search cannot be completed because this site is not assigned to an indexer. Contact your administrator for more information. at Microsoft.SharePoint.Search.Query.Query.CreateQueryProxy(SPSite site) at Microsoft.SharePoint.Search.Query.Query..ctor(SPSite site)” while debugging […]