westconn, thanks a lot. ya, i miss to change that line of code. now i think the program is work smooth already. then i plan to made a command button so can direct access the myPic folder from vb. below is my code
Code:
Option Explicit

Private Const CSIDL_DESKTOP = &H0
Private Const NOERROR = 0

Private Type SHTEMID
    cb As Long
    abID As Byte
End Type
Private Type ITEMIDLIST
    mkid As SHTEMID
End Type

Private Declare Function SHGetSpecialFolderLocation Lib "shell32.dll" (ByVal hwndOwner As Long, ByVal nFolder As Long, pidl As ITEMIDLIST) As Long

Private Declare Function SHGetPathFromIDList Lib "shell32.dll" Alias "SHGetPathFromIDListA" (ByVal pidl As Long, ByVal pszPath As String) As Long

Private Declare Function ShellExecute Lib "shell32.dll" Alias "ShellExecuteA" (ByVal hwnd As Long, ByVal lpOperation As String, ByVal lpFile As String, ByVal lpParameters As String, ByVal lpDirectory As String, ByVal nShowCmd As Long) As Long

Private Const SW_HIDE As Long = 0
Private Const SW_SHOWNORMAL As Long = 1
Private Const SW_SHOWMAXIMIZED As Long = 3
Private Const SW_SHOWMINIMIZED As Long = 2

Dim strDesktop As String

Private Sub Command2_Click()

strDesktop = GetSpecialfolder(CSIDL_DESKTOP)
ShellExecute Me.hwnd, "open", strDesktop & "\webcam\myPic", vbNullString, strDesktop & "\webcam\myPic", SW_SHOWNORMAL

End Sub


Private Sub Form_Load()
Debug.Print "Desktop path: " & GetSpecialfolder(CSIDL_DESKTOP)
End Sub

Private Function GetSpecialfolder(CSIDL As Long) As String
Dim r As Long
Dim IDL As ITEMIDLIST
Dim Path$

    'Get the special folder
    r = SHGetSpecialFolderLocation(100, CSIDL, IDL)
        If r = NOERROR Then
            'Create a buffer
            Path$ = Space$(512)
            'Get the path from the IDList
            r = SHGetPathFromIDList(ByVal IDL.mkid.cb, ByVal Path$)
            'Remove the unnecessary chr$(0)'s
            GetSpecialfolder = Left$(Path, InStr(Path, Chr$(0)) - 1)
            Exit Function
    End If
    GetSpecialfolder = ""
End Function
which is study from my post previously in this thread http://www.vbforums.com/showthread.php?t=550827 However, when i execute it, error variable not found and highlighted on cnt = cnt + 1. what wrong and how to correct it?