hy, why is this code wrong?

vberror: "13"


help

Code:
Option Explicit
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
Private Const LB_FINDSTRING = &H18F
Private Const LB_FINDSTRINGEXACT = &H1A2

Private Sub Command1_Click()
Dim startfrompoint As Long
Dim firstFind As Long
Dim DatumAdd1 As Currency

startfrompoint = -1 'immer von ganz oben suchen
DatumAdd1 = txtDateadd1.Text

firstFind = SendMessage(ListReminderAll.hwnd, LB_FINDSTRINGEXACT, startfrompoint, ByVal "f")

If firstFind <> -1 Then
MsgBox "Eintrag gefunden. Index:" & firstFind
Else
ListReminderAll.AddItem DatumAdd1
End If


End Sub


i dont get it!!

thx Longbow