The remote host closed the connection. The error code is 0x800703E3

I am currently trying to generate a CSV using nhibernate. This error does not occur on my development enviroment but it does on the live site that it's being used on. I have tried fiddling with time out's but this does not seem to have any effect as it's timing out way before it should. The timing is completely random, sometimes it'll be 3 seconds before it times out the next it will be 10 seconds. There doesn't seem to be any real consistancy in the timing.

Stack Trace:

    System.Web.HttpException: The remote host closed the connection. The error code is 0x800703E3.
    at System.Web.Hosting.IIS7WorkerRequest.RaiseCommunicationError(Int32 result, Boolean throwOnDisconnect)
       at System.Web.Hosting.IIS7WorkerRequest.ExplicitFlush()
       at System.Web.HttpResponse.Flush(Boolean finalFlush)
       at Reports.CustomCSVWriter.WritetoHttpStream(String filename, Boolean header)

The code is as follows:

    public class ProductSpreadSheetDownload : CustomCSVWriter
    {
        protected override string[] GetCollection()
        {

            Page.Server.ScriptTimeout = 300;

            IList<Product> products = new List<Product>();
            IStockScheme stockScheme = Fabric.ObjectProvider.Get<IStockScheme>();

            ICriteria criteria = CoreHttpModule.Session.CreateCriteria(typeof(Product))
                .Add(NHibernate.Expression.Expression.IsNotNull(Product.STOCK_CODE))
                .Add(NHibernate.Expression.Expression.Eq(Product.IS_VISIBLE_ON_WEBSITE, true))
                .Add(NHibernate.Expression.Expression.Eq(Product.STOCK_TYPE, StockType.StockItem))
                .Add(NHibernate.Expression.Expression.Not(NHibernate.Expression.Expression.Like(Product.NAME, "%*%")));

            AddCustomCriteria(criteria);

            products = criteria.List<Product>();
            products = Product.RemoveOrphanedAndUnrooted((List<Product>)products);
            Product[] productArray = new Product[products.Count];
            products.CopyTo(productArray, 0);

            double?[] levels = stockScheme.GetStock(productArray, false);
            List<string> productStringList = new List<string>();

            IProductMapper mapper = Fabric.ObjectProvider.Get<IProductMapper>();
            var rootUrl = Fabric.SettingsProvider.ReadSetting<string>("RootUrl", string.Empty);
            string showOutOfStock = Page.Request.QueryString["ShowOutOfStock"];
            int minStockLevel = int.MinValue;
            if (showOutOfStock == "False")
                minStockLevel = 0;

            for (int i = 0; i < productArray.Length; i++)
            {
                if (levels[i] > minStockLevel && levels[i] != null && productArray[i].Parent != null && productArray[i].Parent.IsVisibleOnWebsite)
                {
                    StringBuilder productStringBuilder = new StringBuilder();

                    productStringBuilder.AppendFormat("{0}, ", CleanString(productArray[i].Name));
                    productStringBuilder.AppendFormat("{0}, ", CleanString(productArray[i].StockCode));
                    productStringBuilder.AppendFormat("{0}, ", levels[i]);
                    productStringBuilder.AppendFormat("{0}, ", mapper.GetUrl(productArray[i]) );
                    productStringBuilder.AppendFormat("{0}, ", CleanString(productArray[i].Category));
                    productStringBuilder.AppendFormat("{0}, ", CleanString(productArray[i].SubCategory));
                    productStringBuilder.AppendFormat("{0}, ", CleanString(mapper.GetText(productArray[i], "Description")));
                    productStringBuilder.AppendFormat("{0}, ", mapper.GetImageUrl(productArray[i], "Main"));

                    AddCustomFields(productStringBuilder, mapper);

                    productStringList.Add(productStringBuilder.ToString().Trim().TrimEnd(','));
                }
            }

            string[] productstrings = new string[productStringList.Count];
            productStringList.CopyTo(productstrings, 0);

            return productstrings;
        }

        /// <summary>
        /// Override this method to add custom criteria to the feed
        /// </summary>
        /// <example>
        /// criteria.Add(NHibernate.Expression.Expression.Eq(Product.IS_VISIBLE_ON_WEBSITE, true));
        /// </example>
        protected virtual  void AddCustomCriteria(ICriteria criteria) {}

        /// <summary>
        /// Override this method to add custom fields to the CSV output
        /// </summary>
        /// <example>
        /// productStringBuilder.AppendFormat("{0}, ", mapper.GetImageUrl(productArray[i], "Main"));
        /// </example>
        protected virtual void AddCustomFields(StringBuilder productStringBuilder, IProductMapper mapper) { }


        protected override string Headers()
        {
            string headers = "Name, Stockcode, Stock_Level, URL, Category, SubCategory, Description, Main Image URL";

            return headers;
        }

        /// <summary>
        /// Removes characters that are not safe in a CSV file.
        /// </summary>
        protected static string CleanString(string stringToClean)
        {
            return string.IsNullOrEmpty(stringToClean) ? string.Empty : stringToClean.Replace("\n", " ").Replace(',', ' ');
        }
    }
}