Problem beim benutzen von CreateProcessA und dem Arbeitsverzeichnis

Private Declare Function CreateProcessA Lib "kernel32" (ByVal lpApplicationName As Long, _  
ByVal lpCommandLine As String, ByVal lpProcessAttributes As Long, _
ByVal lpThreadAttributes As Long, ByVal bInheritHandles As Long, _
ByVal dwCreationFlags As Long, ByVal lpEnvironment As Long, _
ByVal lpCurrentDirectory As Long, lpStartupInfo As STARTUPINFO, _
lpProcessInformation As PROCESS_INFORMATION) As Long
Private Const NORMAL_PRIORITY_CLASS = &H20&

Private Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long  


Sub ShellAndWait(ByVal Filename As String)
Dim RetVal As Long
Dim proc As PROCESS_INFORMATION
Dim StartInf As STARTUPINFO

StartInf.cb = Len(StartInf)

'Angegebenes Programm starten  
RetVal = CreateProcessA(0&, Filename, 0&, 0&, 1&, NORMAL_PRIORITY_CLASS, 0&, 0&, StartInf, proc)

'Das eigene Programm anhalten, bis das fremde beendet wurde  
RetVal = WaitForSingleObject(proc.hProcess, INFINITE)
RetVal = CloseHandle(proc.hProcess)