将文件上传到文件夹但不支持GODADDY？

Question

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Collections.Generic;
using System.IO;
public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            BindGrid();

        }
    }
    protected void BindGrid()
    {
        string[] filePaths = Directory.GetFiles(Server.MapPath("~/images/"));
        List<ListItem> files = new List<ListItem>();
        foreach (string filePath in filePaths)
        {
            files.Add(new ListItem(Path.GetFileName(filePath), filePath));
        }
        GridView1.DataSource = files;
        GridView1.DataBind();
    }
    protected void btnUpload_Click(object sender, EventArgs e)
    {
        if (FileUpload1.HasFile)
        {
            FileUpload1.SaveAs(Server.MapPath("~/images/") + FileUpload1.FileName);
            BindGrid();
        }
        else
        {
            Response.Write("Please select file to upload");
        }

    }
    protected void DownloadFile(object sender, EventArgs e)
    {
        string filePath = (sender as LinkButton).CommandArgument;
        Response.ContentType = ContentType;
        Response.AppendHeader("Content-Disposition", "attachment; filename=" + Path.GetFileName(filePath));
        Response.WriteFile(filePath);
        Response.End();
    }
    protected void DeleteFile(object sender, EventArgs e)
    {
        string filePath = (sender as LinkButton).CommandArgument;
        File.Delete(filePath);
        BindGrid();
    }
}

上面的代码将文件上传到文件夹中。该程序在本地成功运行。但我的问题是它无法支持GODADDY服务器。有什么问题？