A cross-site and a file canonicalization problems

Hi. I'm analyzing my code C# with CAT.NET Code Analysis and getting "Sanitize the file path prior to passing it to file system routines" message for File.Move(Path + "\\...

and a cross-site redirection vulnerability “Do not allow off-site redirections to absolute URLs that can be specified by the user” for  Response.Redirect("file:" + Path + "\\...

Is there any solution to these problem?  Thanks!

protected void Button1_Click(object sender, EventArgs e)
{
 if (FileExt == "aa")
 {
   if (ListBox1.SelectedValue == "")
   {
     Response.Redirect("Page1.aspx");
   }
   else
   {
Response.Redirect("file:" + Path + "\\filepath_aa\\" + Status + "\\" + ListBox1.SelectedValue);
   }
 }
 else if (FileExt == "bb")
 {
   if (ListBox1.SelectedValue == "")
   {
     Response.Redirect("Page1.aspx");
   }
   else
   {
Response.Redirect("file:" + Path + "\\filepath_bb\\" + Status + "\\" + ListBox1.SelectedValue);
   }
 }
}

protected void Button2_Click(object sender, EventArgs e)
{
 if (FileExt == "aa")
 {
  if (Status == "New")
  {
   if (ListBox1.SelectedValue == "")
   {
     Response.Redirect("Page1.aspx");
   }
   else
   {
File.Move(Path + "\\filepath_aa\\New\\" + ListBox1.SelectedValue, Path + "\\filepath_aa\\New\\New_Items\\" + ListBox1.SelectedValue);
   }
  }
  else if (Status == "Closed")
  {
   if (ListBox1.SelectedValue == "")
   {
     Response.Redirect("Page1.aspx");
   }
   else
   {
File.Move(Path + "\\filepath_aa\\Closed\\" + ListBox1.SelectedValue, Path + "\\filepath_aa\\Closed\\Closed_Items\\" + ListBox1.SelectedValue);
    }
   }…