Probleme Directory

[Reiji]

Hello,

I am a new on the forum VB.net. I am French and student in computing. I am at present in summer job in the computing. Besides, I am a novice in VB.net. I am spirit to make a program to modify the directory AD of my company. I saw with computer specialists of the DSI of my company, and anybody understands this error. I use Visual Basic 2008 Express
Here is the program:

Module Module1
    Sub main()
        Dim Ldap As DirectoryEntry = New DirectoryEntry("[URL]ldap://name[/URL] AD", "Login", "password")
        Dim searcher As DirectorySearcher = New DirectorySearcher((Ldap))
        searcher.Filter = ""
        For Each result As SearchResult In searcher.FindAll
            Dim DirEntry As DirectoryEntry = result.GetDirectoryEntry()
            DirEntry.Properties("Fonction").Value = ""  
            DirEntry.Properties("Service").Value = ""
            DirEntry.Properties("Société").Value = ""
            DirEntry.Properties("Téléphone").Value = ""
            DirEntry.Properties("Portable").Value = ""
            DirEntry.Properties("Fax").Value = ""
            DirEntry.Properties("Mail").Value = ""
            DirEntry.CommitChanges() 
        Next
    End Sub
End Module

My probleme is the following one. When I launch the program, he indicates me that I have an error at the level of this line :

DirEntry.CommitChanges()

and

ForEach result As SearchResult In searcher.FindAll

He indicates me that :

The Exception. DirectoryServicesCOMException was not managed:
The Attribute or the value of service of specified directory does not exist. (The Exception of HRESULT: 0x8007200A)

And in the fenetre of execution he puts me:

An exception of first luck of type ' System. DirectoryServices. DirectoryServicesCOMException ' occurred in System. DirectoryServices.dll

I does not really understand. The program is to register in VB, can be that it is the error. I have to try how to register in VB.net but I have not to find.

Thank you in advance

Reiji