Für alle, die es interessiert hier die Lösung:
Olaf

Imports System.Runtime.InteropServices

Public Class classNetFile

    Declare Unicode Function NetFileEnum Lib "netapi32.dll" (ByVal
servername As String, ByVal basepath As String, ByVal username As
String, _
            ByVal level As Integer, ByRef bufptr As IntPtr, ByVal
prefmaxlen As Integer, ByRef entriesread As Integer, _
            ByRef totalentries As Integer, ByVal resume_handle As
IntPtr) As Integer

    Declare Unicode Function NetFileClose Lib "netapi32.dll" (ByVal
servername As String, ByVal fileid As Integer) As Integer

    Declare Unicode Function NetApiBufferFree Lib "netapi32.dll" (ByVal
buffer As IntPtr) As Integer

    <StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Auto,
Pack:=4)> _
    Structure FILE_INFO_3
        Dim fi3_id As Integer
        Dim fi3_permission As Integer
        Dim fi3_num_locks As Integer
        Dim fi3_pathname As String
        Dim fi3_username As String
    End Structure

       Public Function EnumNetFile(ByVal ServerName As String) As
Integer
        If ServerName = "." Then ServerName = Nothing
        Const MAX_PREFERRED_LENGTH As Integer = -1
        Dim dwReadEntries As Integer
        Dim dwTotalEntries As Integer
        Dim pBuffer As IntPtr = IntPtr.Zero
        Dim pCurrent As FILE_INFO_3 = New FILE_INFO_3

        Dim dwStatus As Integer = NetFileEnum(ServerName, Nothing,
Nothing, 3, pBuffer, MAX_PREFERRED_LENGTH, dwReadEntries,
dwTotalEntries, IntPtr.Zero)
        If dwStatus = 0 Then
            Dim dwIndex As Integer = 0
            While dwIndex < dwReadEntries
                Dim iPtr As IntPtr = New IntPtr(pBuffer.ToInt32 +
(dwIndex * Marshal.SizeOf(pCurrent)))
                pCurrent = CType(Marshal.PtrToStructure(iPtr,
GetType(FILE_INFO_3)), FILE_INFO_3)
                Console.WriteLine("dwIndex={0}", dwIndex)
                Console.WriteLine(" id={0}", pCurrent.fi3_id)
                Console.WriteLine(" num_locks={0}",
pCurrent.fi3_num_locks)
                Console.WriteLine(" pathname={0}",
pCurrent.fi3_pathname)
                Console.WriteLine(" permission={0}",
pCurrent.fi3_permission)
                Console.WriteLine(" username={0}",
pCurrent.fi3_username)