Error during remote access to Active Directory

[Frank_00001]

I'm trying to use Active Directory to get a list of users that are in the
same directory as the logon user. I'm trying to do this as a Web App written
in C# using Windows Security and Impersonation. When running from the local
host I have no problem; but when I try the same thing remotely I get the
error "System.Runtime .InteropService s.COMException" on the second hit on
Active Directory, the first hit works fine. I used to get the same error all
the time until I started using Impersonation.

Any suggestions as to what might be the issue?

Below is the specific code in question. It errors out at "DirectoryE ntry
child"
private void Page_Load(objec t sender, System.EventArg s e)
{
// Put user code to initialize the page here
if (!IsPostBack)
{
DirectoryEntry user_entry = new
DirectoryEntry( "LDAP://DOMAIN.org/DC=DOMAIN,DC=or g");
DirectorySearch er mySearcher = new DirectorySearch er(user_entry);
Session["User.ID"] = User.Identity.N ame.ToString(). Substring(12);
mySearcher.Filt er = ("(CN=" + Session["User.ID"].ToString() + ")");
SearchResult resEnt = mySearcher.Find One();

Session["User.Name"] =
resEnt.GetDirec toryEntry().Pro perties["DisplayNam e"].Value.ToString ();
Session["User.Path"] = resEnt.Path.ToS tring();
Session["User.CN"] =
resEnt.GetDirec toryEntry().Pro perties["CN"].Value.ToString ();
lblWelcome.Text = "Welcome, " + Session["User.Name"].ToString();

string TempString = resEnt.Path.ToS tring().Replace ("CN=" +
Session["User.CN"].ToString() + ",", "");
DirectoryEntry local_entry = new DirectoryEntry( TempString);
//this is where the error occurs
foreach(Directo ryEntry child in local_entry.Chi ldren)
{
if (child.Properti es.Contains("Ma il") == true)
{
string tempString1 = child.Propertie s["DisplayNam e"].Value.ToString ();
string tempString2 = child.Propertie s["Mail"].Value.ToString ();
ListItem tempItem = new ListItem(tempSt ring1,tempStrin g2);
ddlNominee.Item s.Add(tempItem) ;
}
}
}
}