I have an httpmodule to catch errors when people try to upload too large a file.  But I am getting a "Value does not fall within the expected range" error when trying to redirect to an error page.  This is my BeginRequest code.

HttpRuntimeSection runTime = (HttpRuntimeSection)WebConfigurationManager.GetSection("system.web/httpRuntime");

//Approx 100 Kb(for page content) size has been deducted because the maxRequestLength proprty is the page size, not only the file upload size
int maxRequestLength = (runTime.MaxRequestLength - 100) * 1024;

//This code is used to check the request length of the page and if the request length is greater than
//MaxRequestLength then retrun to the same page with extra query string value action=exception
HttpContext context = ((HttpApplication)sender).Context;

if (context.Request.ContentLength > maxRequestLength)
{
    IServiceProvider provider = (IServiceProvider)context;
    HttpWorkerRequest workerRequest = (HttpWorkerRequest)provider.GetService(typeof(HttpWorkerRequest));

    // Check if body contains data
    if (workerRequest.HasEntityBody())
    {
        // get the total body length
        int requestLength = workerRequest.GetTotalEntityBodyLength();

        // Get the initial bytes loaded
        int initialBytes = 0;

        if (workerRequest.GetPreloadedEntityBody() != null)
            initialBytes = workerRequest.GetPreloadedEntityBody().Length;

        if (!workerRequest.IsEntireEntityBodyIsPreloaded())
        {
            byte[] buffer = new byte[512000];

            // Set the received bytes to initial bytes before start reading
            int receivedBytes = initialBytes;

            while (requestLength - receivedBytes >= initialBytes)
            {
                // Read another set of bytes
                initialBytes = workerRequest.ReadEntityBody(buffer, buffer.Length);

                // Update the received bytes
                receivedBytes += initialBytes;
            }

            initialBytes = workerRequest.ReadEntityBody(buffer, requestLength - receivedBytes);

        }

    }

    context.Response.Redirect("/error-pages/upload-error.aspx");
}

Does anyone know what could be wrong.  The only think I can find on google is IIS rejecting new lines in headers.  But I still get the error when I clear the headers.