We have found a fix for this bug. You can add a try catch around the piece of code throwing the Exception and log the specific Exception using the Log class. You can do this by adding in the following code in TemplateContent.cs. The attached file is a screen shot of where to add the fix. Replace the highlighted line with the following code.

protected override void CreateChildControls()

    {

        if (_template != null)
        {
            try
            {
                PlaceHolder ctl = new PlaceHolder();
                _template.InstantiateIn(ctl);
                Controls.Add(ctl);
            }
            catch (HttpException ex) {
                Log newLog = new Log();
                newLog.AddLogEntry(HttpContext.Current.Request, ex);
            }
        }
    }

You will also have to add the following "using" statement to the TemplateControl.cs file: "using System.Web.SessionState;".