Error in file path

Dear All,

i had use  upload file function in ajak control tool kits, but it shows error. kindly advise. thank you

protected void ajaxUpload1_OnUploadComplete(object sender, AjaxControlToolkit.AjaxFileUploadEventArgs e)
{

string filePath = "\\10.238.31.21\\UploadFile\\" + Path.GetFileName(e.FileName);
AjaxFileUpload1.SaveAs(filePath);
DataUpload(filePath);
}