Http-команду, до доступ к пути '/PoshandDangles/им-моложе-чем-вы-п22/' - не допускается. после того, как я нажму на кнопку Добавить в корзину покупок для Paypal. Я не знаю, откуда берется эта ошибка...

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;

public partial class Product : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        // Retrieve ProductID from the query string
        string productId = Request.QueryString["ProductID"];
        // Retrieves product details
        ProductDetails pd = CatalogAccess.GetProductDetails(productId);
        // Does the product exist?
        if (pd.Name != null)
        {
            PopulateControls(pd);
        }
        else
        {
            Server.Transfer("~/NotFound.aspx");
        }
        // 301 redirect to the proper URL if necessary
        Link.CheckProductUrl(Request.QueryString["ProductID"]);
    }

    // Fill the control with data
    private void PopulateControls(ProductDetails pd)
    {
        // Display product details
        titleLabel.Text = pd.Name;
        descriptionLabel.Text = pd.Description;
        priceLabel.Text = String.Format("{0:c}", pd.Price);
        productImage.ImageUrl = Link.ToProductImage(pd.Image);
        // Set the title of the page
        this.Title = PoshandDanglesConfiguration.SiteName + ": " + pd.Name;

        // obtain the attributes of the product
        DataTable attrTable =
          CatalogAccess.GetProductAttributes(pd.ProductID.ToString());

        // temp variables
        string prevAttributeName = "";
        string attributeName, attributeValue, attributeValueId;

        // current DropDown for attribute values
        Label attributeNameLabel;
        DropDownList attributeValuesDropDown = new DropDownList();

        // read the list of attributes
        foreach (DataRow r in attrTable.Rows)
        {
            // get attribute data
            attributeName = r["AttributeName"].ToString();
            attributeValue = r["AttributeValue"].ToString();
            attributeValueId = r["AttributeValueID"].ToString();

            // if starting a new attribute (e.g. Color, Size)
            if (attributeName != prevAttributeName)
            {
                prevAttributeName = attributeName;
                attributeNameLabel = new Label();
                attributeNameLabel.Text = attributeName + ": ";
                attributeValuesDropDown = new DropDownList();
                attrPlaceHolder.Controls.Add(attributeNameLabel);
                attrPlaceHolder.Controls.Add(attributeValuesDropDown);
            }

            // add a new attribute value to the DropDownList
            attributeValuesDropDown.Items.Add(new ListItem(attributeValue, attributeValueId));
        }
    }
    protected void AddToCartButton_Click(object sender, EventArgs e)
    {

        // Retrieve ProductID from the query string
        string productId = Request.QueryString["ProductID"];
        // Retrieves product details
        ProductDetails pd = CatalogAccess.GetProductDetails(productId);

        // Retrieve the selected product options
        string options = "";
        foreach (Control cnt in attrPlaceHolder.Controls)
        {
            if (cnt is Label)
            {
                Label attrLabel = (Label)cnt;
                options += attrLabel.Text;
            }

            if (cnt is DropDownList)
            {
                DropDownList attrDropDown = (DropDownList)cnt;
                options += attrDropDown.Items[attrDropDown.SelectedIndex] + "; ";
            }
        }

        // The Add to Cart link
        string productUrl = Link.ToProduct(pd.ProductID.ToString());
        string destination = Link.ToPayPalAddItem(productUrl, pd.Name, pd.Price, options);
        Response.Redirect(destination);
    }
}