Errors generated during processing using UrlTransformer

[tin-tin]

We are currently experiencing the following errors intermittently with RR. It happens during processing of JS and CSS files and prevents any of the requests from being reduced. We are doing a URL transformation as the site is served via HTTPS with SSL offloaded to an external device. When the app pool recycles it is back to normal again for a small period of time eventually the errors return and RR stops.

Any help would greatly be appreciated.

Key: 24a16d6e-139d-d01f-3d20-9f22893992af
    First errored on: 07/03/2013 10:06:05
    Last errored on: 07/03/2013 10:06:05
    Number: 4
    Exception #1: There were errors reducing /WebResource.axd?d=2ISJTlTccIWS9pXm6PbOF9iT9qVKvVVPpO8qIDY-kFfakaZIONcNnYdo4jogzKJpP02szMBoEPGo3-ww1u04HM_y4k41&t=634604622479085897
    Exception #2: Value does not fall within the expected range.
    Stack Trace#2:

   at System.Runtime.InteropServices.Marshal.ThrowExceptionForHRInternal(Int32 errorCode, IntPtr errorInfo)
   at System.Web.Util.Misc.ThrowIfFailedHr(Int32 hresult)
   at System.Web.Hosting.IIS7WorkerRequest.GetServerVariableInternal(String name)
   at System.Web.HttpRequest.get_Url()
   at XXXX.UI.Core.FirstRequestInitialisation.GetFullyQualifiedHost(HttpContext context)
   at XXXX.UI.Global.<>c__DisplayClass1.b__0(HttpContextBase cxt, String x, String y)
   at RequestReduce.Utilities.UriBuilder.BuildResourceUrl(Guid key, String signature, Type resourceType)
   at RequestReduce.Utilities.UriBuilder.BuildResourceUrl[T](Guid key, String signature)
   at RequestReduce.Utilities.UriBuilder.BuildResourceUrl[T](Guid key, Byte[] bytes)
   at RequestReduce.Reducer.HeadResourceReducerBase`1.Process(Guid key, String urls)
   at RequestReduce.Module.ReducingQueue.ProcessQueuedItem()

Key: ec6bb0b8-0216-36a7-e2de-99ae27987573
    First errored on: 07/03/2013 09:30:40
    Last errored on: 07/03/2013 09:30:40
    Number: 5
    Exception #1: There were errors reducing http://site.com/css/style.css::http://site.com/css/jquery.bxslider.css::http://site.com/css/jquery-ui-1.9.2.custom.css::http://site.com/css/jquery-ui-1.9.2.custom.min.css::
    Exception #2: Value does not fall within the expected range.
    Stack Trace#2:

   at System.Runtime.InteropServices.Marshal.ThrowExceptionForHRInternal(Int32 errorCode, IntPtr errorInfo)
   at System.Web.Util.Misc.ThrowIfFailedHr(Int32 hresult)
   at System.Web.Hosting.IIS7WorkerRequest.GetServerVariableInternal(String name)
   at System.Web.HttpRequest.get_Url()
   at XXXX.UI.Core.FirstRequestInitialisation.GetFullyQualifiedHost(HttpContext context)
   at XXXX.UI.Global.<>c__DisplayClass1.b__0(HttpContextBase cxt, String x, String y)
   at RequestReduce.Reducer.CssReducer.MakeRelativeUrlsAbsoluteAndRemoveComments(String originalCss, String parentCssUrl)
   at RequestReduce.Reducer.CssReducer.ProcessCss(String url)
   at RequestReduce.Reducer.CssReducer.ProcessResource(Guid key, IEnumerable`1 urls)
   at RequestReduce.Reducer.HeadResourceReducerBase`1.Process(Guid key, String urls)
   at RequestReduce.Module.ReducingQueue.ProcessQueuedItem()

config in use:

<RequestReduce cssProcesingDisabled="false" javascriptProcessingDisabled="false" imageSpritingDisabled="true" ipFilterList=""  />

And the URL transformation code:

  protected void Application_BeginRequest(object sender, EventArgs e)
        {
            if (RequestReduce.Api.Registry.UrlTransformer == null)
            {
                HttpApplication app = (HttpApplication)sender;
                HttpContext context = app.Context;

                RequestReduce.Api.Registry.UrlTransformer =
                   (cxt, x, y) => y.Replace(FirstRequestInitialisation.GetFullyQualifiedHost(context), "").Replace(FirstRequestInitialisation.GetHostWithoutPort(context), "");
            }
        }