controlar el winamp desde VB

Creo que es mas fácil de esta manera:

En un Módulo

Option Base 1

'Funciones para poder usar el Winamp
Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As Long) As Long
Declare Function PostMessage Lib "user32" Alias "PostMessageA" (ByVal WndID As Long, ByVal wMsg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal WndID As Long, ByVal wMsg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
Declare Function CopyDataSendMessage Lib "user32" Alias "SendMessageA" (ByVal WndID As Long, ByVal wMsg As Long, ByVal wParam As Long, ByRef lParam As COPYDATASTRUCT) As Long
Declare Function lstrcpy Lib "kernel32" Alias "lstrcpyA" (ByVal lpString1 As String, ByVal lpString2 As String) As Long
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

Type COPYDATASTRUCT
dwData As Long
cbData As Long
lpData As Long
End Type

Public hWndWinamp As Long
Public RetVal As Long

'Windows Constantes
Public Const WM_COMMAND = &H111
Public Const WM_COPYDATA = &H4A
Public Const WM_USER = &H400

'Winamp Constantes
Public Const waClose As Long = 40001
Public Const waPlay As Long = 40045
Public Const waStop As Long = 40047
Public Const waPause As Long = 40046
Public Const waPreviousTrack As Long = 40044
Public Const waNextTrack As Long = 40048
Public Const waForward5Sec As Long = 40148
Public Const waRewind5Sec As Long = 40144
Public Const waRaiseVolume As Long = 40058
Public Const waLowerVolume As Long = 40059

Public Const waShuffle As Long = 252
Public Const waGetStatus As Long = 104
Public Const waGetPosLen As Long = 105
Public Const waSetPos As Long = 106
Public Const waSetVolume As Long = 122

'Winamp Constates del estado ejecucción
Public Const waPlaying As Long = 1
Public Const waPaused As Long = 3
Public Const waStopped As Long = 0
Public Const waPlayStatusError As Long = -1
'Iniciar Winamp
Public Sub StartWinamp(waclass As String)
Dim dirWA As String
dirWA = "C:\Archivos de programa\Winamp\winamp.exe /CLASS=" & Chr(34) & waclass & Chr(34)
Shell dirWA, vbMinimizedNoFocus ‘ abre el Winamp minimizado
End Sub
'Salir Winamp
Public Sub CloseWinamp(waclass As String)
hWndWinamp = FindWindow(waclass, 0)
If hWndWinamp = 0 Then
Exit Sub
End If
RetVal = SendMessage(hWndWinamp, WM_COMMAND, waClose, 0)
End Sub

'Ejecuta la canción
Public Sub PlayTrack(waclass As String, Optional PostMess As Boolean = True)
hWndWinamp = FindWindow(waclass, 0)
If hWndWinamp = 0 Then
Exit Sub
End If
If PostMess Then
PostIt waPlay
Else
SendIt waPlay
End If
End Sub
'Detiene la canción
Public Sub StopTrack(waclass As String, Optional PostMess As Boolean = True)
hWndWinamp = FindWindow(waclass, 0)
If hWndWinamp = 0 Then
Exit Sub
End If
If PostMess Then
PostIt waStop
Else
SendIt waStop
End If
End Sub
'Pausa la canción
Public Sub PauseTrack(waclass As String, Optional PostMess As Boolean = True)
hWndWinamp = FindWindow(waclass, 0)
If hWndWinamp = 0 Then
Exit Sub
End If
If PostMess Then
PostIt waPause
Else
SendIt waPause
End If
End Sub
'Canción anterior
Public Sub PreviousTrack(waclass As String, Optional PostMess As Boolean = True)
hWndWinamp = FindWindow(waclass, 0)
If hWndWinamp = 0 Then
Exit Sub
End If
If PostMess Then
PostIt waPreviousTrack
Else
SendIt waPreviousTrack
End If
End Sub
'Canción siguiente
Public Sub NextTrack(waclass As String, Optional PostMess As Boolean = True)
hWndWinamp = FindWindow(waclass, 0)
If hWndWinamp = 0 Then
Exit Sub
End If
If PostMess Then
PostIt waNextTrack
Else
SendIt waNextTrack
End If
End Sub
'Avanza 5 segundos la canción
Public Sub Forward5Sec(waclass As String, Optional PostMess As Boolean = True)
hWndWinamp = FindWindow(waclass, 0)
If hWndWinamp = 0 Then
Exit Sub
End If
If PostMess Then
PostIt waForward5Sec
Else
SendIt waForward5Sec
End If
End Sub
'Retrocede 5 segundos la canción
Public Sub Rewind5Sec(waclass As String, Optional PostMess As Boolean = True)
hWndWinamp = FindWindow(waclass, 0)
If hWndWinamp = 0 Then
Exit Sub
End If
If PostMess Then
PostIt waRewind5Sec
Else
SendIt waRewind5Sec
End If
End Sub

'Obtiene el estado del Winamp
Public Function GetStatus(waclass As String) As Long
hWndWinamp = FindWindow(waclass, 0)
If hWndWinamp = 0 Then
Exit Function
End If
GetStatus = SendMessage(hWndWinamp, WM_USER, 0, waGetStatus)
End Function
'Funciones para los mensajes
Private Sub PostIt(Action As Long)
Dim n As Date
n = Now
Do
RetVal = PostMessage(hWndWinamp, WM_COMMAND, Action, 0)
Debug.Print "post", Now - n, 5 / 86400
If RetVal = 0 Then
If Now - n > 5 / 86400 Then
MsgBox "Couldn't queue message for 5 seconds: " & Action
Exit Do
End If
End If
Loop Until RetVal <> 0
End Sub
Private Sub SendIt(Action As Long)
RetVal = SendMessage(hWndWinamp, WM_COMMAND, Action, 0)
End Sub

y esto en el form:
If Text1.Text = "abrir_win" Then StartWinamp WAClase ' abre el winamp
If Text1.Text = "cerrar_win" Then CloseWinamp WAClase 'cierra el winamp
If Text1.Text = "atras_win" Then PreviousTrack WAClase 'tema anterior winamp
If Text1.Text = "play_win" Then PlayTrack WAClase 'reproduce el winamp
If Text1.Text = "pause_win" Then PauseTrack WAClase 'pause ene l winamp
If Text1.Text = "stop_win" Then StopTrack WAClase 'detiene el tema en el winamp
If Text1.Text = "adelante_win" Then NextTrack WAClase 'el tema sig del winamp
If Text1.Text = "RW_win" Then Rewind5Sec WAClase ' retrocede 5 seg winamp
If Text1.Text = "FF_win" Then Forward5Sec WAClase 'adelanta 5 seg winamp

End Sub

Nota2: Todo está en visual basic