Adding HtmlHead cause error on Rendering

Before the execution of "head.Controls.Add(title)":
      1 - When I watch "head" it shows - "{InnerText = ""}"
      2 - When I watch "title" it shows - "{System.Web.UI.HtmlControls.HtmlTitle}"
After the exectuion of head.Controls.Add(title)":
      When I watch "head" it shows "{InnerText = (InnerText) threw an exception of type System.Web.HttpException.}"
This cause error "Request is not available in this context" when line "page.RenderControl(htw)" is executed.
When I exclude the lines "Dim head As HtmlHead = buildHeadControl()"Go to the complete details ...