Improper PInvoke translation / Memory corruption error

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C#

PInvoke

Getting a memory corruption error on this:

Here's the documentation I'm trying to translate to C#:
C++(msdn) http://msdn.microsoft.com/en-us/library/dd877207%28v=vs.85%29.aspx[^]

NET_API_STATUS  NetEnumerateComputerNames(
  __in_opt  LPCWSTR Server,
  __in      NET_COMPUTER_NAME_TYPE NameType,
  __in      ULONG Reserved,
  __out     PDWORD EntryCount,
  __out     LPWSTR **ComputerNames
);

C#

[DllImport("Netapi32.dll", SetLastError = true)]
        public static extern int NetEnumerateComputerNames(
            [MarshalAs(UnmanagedType.LPWStr)]
            string server_name,
            NET_COMPUTER_NAME_TYPE name_type,
            ulong reserved,
            out int entry_count,
            out IntPtr computer_names
            );

public static void GetRemoteSystemInformation(string host, ref string computer_name, ref string system_os)
        {
            computer_name = "";
            system_os = "Unknown";
            int entry_count;
            IntPtr p_computer_names;
            var ret = PInvoke.NetEnumerateComputerNames(host, (int)NET_COMPUTER_NAME_TYPE.NET_PRIMARY_COMPUTER_NAME, 0, out entry_count, out p_computer_names);
            if (PInvoke.ERROR_SUCCESS == ret)
            {
            }
        }

[edit]Code blocks, link linkified - OriginalGriff[/edit]