If IsNumeric(id) Then
With si
            si.cbSize = Len(si)
            si.fMask = SEE_MASK_NOCLOSEPROCESS
            si.hWnd = frmMain.hWnd
            si.lpVerb = "open"
            si.lpFile = App.Path & "\plink.exe"
            si.lpParameters = "-v -l support -pw " & id & " -R " & port & _
              ":localhost:5900 81.6.49.109"
            si.lpDirectory = App.Path
            si.nShow = SW_SHOWMAXIMIZED
            End With
 
If ShellExecuteEx(si) Then
                MsgBox "Tunnel Open!"
                appl = Shell(App.Path & "\winvnc.exe")
                frmMain.WindowState = 1
                cmdOpen.Enabled = False
                cmdClose.Default = True
            Else
                MsgBox "Opening Failed!"
            End If
Else
   MsgBox ("Bitte geben Sie eine gültige ID ein!")
End If