would anyone have a working example of an amazon ITEMLOOKUP ?>

i have the following code but it does not seem to work:

string ISBN = "0393326381";
            string ASIN = "";

            if (!(string.IsNullOrEmpty(ISBN) && string.IsNullOrEmpty(ASIN)))
            {
                AWSECommerceServicePortTypeChannel service = new AWSECommerceServicePortTypeChannel();
                ItemLookup lookup = new ItemLookup();
                ItemLookupRequest request = new ItemLookupRequest();

                lookup.AssociateTag = secretKey;
                lookup.AWSAccessKeyId = accessKeyId;
                if (string.IsNullOrEmpty(ASIN))
                {
                    request.IdType = ItemLookupRequestIdType.ISBN;
                    request.ItemId = new string[] { ISBN.Replace("-", "") };
                }
                else
                {
                    request.IdType = ItemLookupRequestIdType.ASIN;
                    request.ItemId = new string[] { ASIN };
                }
                request.ResponseGroup = new string[] { "OfferSummary" };

                lookup.Request = new ItemLookupRequest[] { request };
                response = service.ItemLookup(lookup);

                if (response.Items.Length > 0 && response.Items[0].Item.Length > 0)
                {
                    Item item = response.Items[0].Item[0];
                    if (item.MediumImage == null)
                    {
                        //bookImageHyperlink.Visible = false;
                    }
                    else
                    {
                        //bookImageHyperlink.ImageUrl = item.MediumImage.URL;
                    }
                    //bookImageHyperlink.NavigateUrl = item.DetailPageURL;
                    //bookTitleHyperlink.Text = item.ItemAttributes.Title;
                    //bookTitleHyperlink.NavigateUrl = item.DetailPageURL;
                    if (item.OfferSummary.LowestNewPrice == null)
                    {
                        if (item.OfferSummary.LowestUsedPrice == null)
                        {
                            //priceHyperlink.Visible = false;
                        }
                        else
                        {
                            //priceHyperlink.Text = string.Format("Buy used {0}", item.OfferSummary.LowestUsedPrice.FormattedPrice);
                            //priceHyperlink.NavigateUrl = item.DetailPageURL;
                        }
                    }
                    else
                    {
                        //priceHyperlink.Text = string.Format("Buy new {0}", item.OfferSummary.LowestNewPrice.FormattedPrice);
                        //priceHyperlink.NavigateUrl = item.DetailPageURL;
                    }
                    if (item.ItemAttributes.Author != null)
                    {
                        //authorLabel.Text = string.Format("By {0}", string.Join(", ", item.ItemAttributes.Author));
                    }
                    else
                    {
                        //authorLabel.Text = string.Format("By {0}", string.Join(", ", item.ItemAttributes.Creator.Select(c => c.Value).ToArray()));
                    }
                    /*
                    ItemLink link = item.ItemLinks.Where(i => i.Description.Contains("Wishlist")).FirstOrDefault();
                    if (link == null)
                    {
                        //wishListHyperlink.Visible = false;
                    }
                    else
                    {
                        //wishListHyperlink.NavigateUrl = link.URL;
                    }
                     * */
                }
            }

        }

the problem is with this:

thisshould be defined differently but i do not know how AWSECommerceServicePortTypeChannel service = new AWSECommerceServicePortTypeChannel();