You also need to add any namespaces to your Web.config razor configuration, e.g:
<system.web.webPages.razor>
<host factoryType="System.Web.Mvc.MvcWebRazorHostFactory, System.Web.Mvc, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
<pages pageBaseType="ServiceStack.Razor.ViewPage">
<namespaces>
<add namespace="ServiceStack"/>
<add namespace="ServiceStack.Html"/>
<add namespace="ServiceStack.Razor"/>
<add namespace="ServiceStack.Text"/>
<add namespace="ServiceStack.OrmLite"/>
<add namespace="Tribe.Guru.SelfHost"/>
</namespaces>
</pages>
</system.web.webPages.razor>