title: Can someone help me understand this stack trace?
body: <p>I am getting an <code>Object reference not set to an instance of an object</code> error from a page on my site emailed through to me. When I go to that page, I don't get any errors though. Could someone explain what "could" be happening based on this stack trace. I know something is wrong with the render but I don't know where to go from here ... Thanks.</p>
  
  <pre><code>at ASP.controls_si_item_ascx.__Render__control1(HtmlTextWriter __w, Control parameterContainer)
  at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
  at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer)
  at System.Web.UI.Control.Render(HtmlTextWriter writer)
  at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter)
  at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter)
  at System.Web.UI.Control.RenderControl(HtmlTextWriter writer)
  at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
  at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer)
  at System.Web.UI.Control.Render(HtmlTextWriter writer)
  at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter)
  at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter)
  at System.Web.UI.Control.RenderControl(HtmlTextWriter writer)
  at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
  at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer)
  at System.Web.UI.Control.Render(HtmlTextWriter writer)
  at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter)
  at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter)
  at System.Web.UI.Control.RenderControl(HtmlTextWriter writer)
  at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
  at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer)
  at System.Web.UI.HtmlControls.HtmlContainerControl.Render(HtmlTextWriter writer)
  at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter)
  at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter)
  at System.Web.UI.Control.RenderControl(HtmlTextWriter writer)
  at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
  at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer)
  at System.Web.UI.HtmlControls.HtmlForm.RenderChildren(HtmlTextWriter writer)
  at System.Web.UI.HtmlControls.HtmlContainerControl.Render(HtmlTextWriter writer)
  at System.Web.UI.HtmlControls.HtmlForm.Render(HtmlTextWriter output)
  at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter)
  at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter)
  at System.Web.UI.HtmlControls.HtmlForm.RenderControl(HtmlTextWriter writer)
  at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
  at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer)
  at System.Web.UI.Control.Render(HtmlTextWriter writer)
  at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter)
  at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter)
  at System.Web.UI.Control.RenderControl(HtmlTextWriter writer)
  at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
  at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer)
  at System.Web.UI.Page.Render(HtmlTextWriter writer)
  at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter)
  at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter)
  at System.Web.UI.Control.RenderControl(HtmlTextWriter writer)
  at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
  </code></pre>