Profile: Cbauto

Really can't get this to work getting the following error:

An error occurred during the compilation of a resource required to process this request. Please review the following specific error details and modify your source code appropriately.
h:----->\TopicDetails.cshtml

'IHtmlHelper<TopicModel>' does not contain a definition for 'Widget' and no extension method 'Widget' accepting a first argument of type 'IHtmlHelper<TopicModel>' could be found (are you missing a using directive or an assembly reference?)

I've copied the above exactly and inserted the correct names. What could be the error?