With argv0's C code I have converted a lot of the code to VB .NET. I am getting 0 returned by SendMessage though and can't find a solution to the problem. Anyone have any insight?

The New Win32Exception(Marshal.GetLastWin32Error()).Message I get after I execute SendMessage is: "The specified procedure could not be found"

I am getting a return of 0 from SendMessage and can't figure out why. How can I find out why it's getting an error or does anyone know what's wrong?

Code:
    Private Const WM_MCOMMAND As Integer = &H102 + 200
    Private Const FILE_MAP_ALL_ACCESS As Integer = &H1 Or &H2 Or &H4 Or &H8 Or &H10 Or &HF0000
    Private Const PAGE_READWRITE As Integer = &H4
    Private Const INVALID_HANDLE_VALUE As Integer = -1

    Declare Auto Function SendMessage Lib "user32" ( _
        ByVal hWnd As IntPtr, _
        ByVal Msg As Integer, _
        ByVal wParam As Integer, _
        ByVal lParam As Integer) As Integer

    Private Declare Auto Function CreateFileMapping Lib "kernel32" ( _
        ByVal hFile As Integer, _
        ByVal lpFileMappingAttributes As Integer, _
        ByVal flProtect As Integer, _
        ByVal dwMaximumSizeHigh As Integer, _
        ByVal dwMaximumSizeLow As Integer, _
        ByVal lpName As String) As IntPtr

    Declare Function MapViewOfFile Lib "kernel32" Alias "MapViewOfFile" ( _
        ByVal hFileMappingObject As IntPtr, _
        ByVal dwDesiredAccess As Integer, _
        ByVal dwFileOffsetHigh As Integer, _
        ByVal dwFileOffsetLow As Integer, _
        ByVal dwNumberOfBytesToMap As UIntPtr) As IntPtr

    Private Declare Auto Function wsprintf Lib "user32" ( _
        ByVal lpOut As IntPtr, _
        ByVal lpFmt As String) As Integer

    Private Declare Auto Function UnmapViewOfFile Lib "kernel32" ( _
        ByVal lpBaseAddress As IntPtr) As Boolean

    Public Declare Auto Function CloseHandle Lib "kernel32.dll" ( _
        ByVal hObject As IntPtr) As Boolean

    Function SendCommand(ByVal hwnd As IntPtr, ByVal command As String) As Boolean
        Dim hMapFile As IntPtr
        Dim mData As IntPtr
        Dim NumberOfBytes As UIntPtr

        Dim intWsprintf As Integer
        Dim intSendmessage As Integer

        ' hwnd = 459282
        ' command = "/msg XBN`grind test"

        ' Returns: 1684
        hMapFile = CreateFileMapping(INVALID_HANDLE_VALUE, 0, PAGE_READWRITE, 0, 4096, "mIRC")

        ' Returns: 72548352
        mData = MapViewOfFile(hMapFile, FILE_MAP_ALL_ACCESS, 0, 0, NumberOfBytes)

        ' Returns: 18
        intWsprintf = wsprintf(mData, command)

        ' Returns: 0
        intSendmessage = (SendMessage(hwnd, WM_MCOMMAND, 1, 0))

        ' Returns: False
        UnmapViewOfFile(mData)

        ' Returns: False
        CloseHandle(hMapFile)

        Return True
    End Function