MVC Mini Profiler Exception on MiniProfiler.Stop()

I'm just added Mini Profiler to my MVC3 project with nuget and I've followed the basic steps to get it set up. Starting the profile on Application_BeginRequest() and stopping it on Application_EndRequest()

    protected void Application_BeginRequest()
    {
        if (Request.IsLocal)
        {
            MiniProfiler.Start();
        }

    }

    protected void Application_EndRequest()
    {
        MiniProfiler.Stop();
    }

MiniProfiler.Stop() is throwing an exception - "Server cannot append header after HTTP headers have been sent."

Has anybody else seen this?