esto es por que Sleep es una llamada al Api de Windows
debes declarala antes de poder usarla
Ejemplo tomado de AllApi.Net
'This project needs a button
Private Declare Sub Sleep Lib "kernel32" (ByVal dwMilliseconds As Long)
Private Sub Command1_Click()
'KPD-Team 1998
'URL:
http://www.allapi.net/
'E-Mail:
[email protected]
Me.Caption = "Your system will sleep 5 sec."
'Sleep for 5000 milliseconds
Sleep 5000
Me.Caption = ""
End Sub
Private Sub Form_Load()
Me.Caption = ""
Command1.Caption = "Sleep ..."
End Sub