Call External Function

[abazabam]

How do I call an external function? I tried this code but it always crashes:

Private Declare Function FreeLibrary Lib "kernel32" (ByVal hLibModule As Long) As Long

Private Declare Function LoadLibrary Lib "kernel32" Alias "LoadLibraryA" (ByVal lpLibFileName As String) As Long

Private Declare Function GetProcAddress Lib "kernel32" (ByVal hModule As Long, ByVal lpProcName As String) As Long

Private Declare Function CallWindowProc Lib "user32" Alias "CallWindowProcA" (ByVal lpPrevWndFunc As Long, ByVal hWnd As Long, ByVal Msg As Any, ByVal wParam As Any, ByVal lParam As Any) As Long

Private Sub Form_Load()
On Error Resume Next

Dim lb As Long, pa As Long

lb = LoadLibrary("zlib.dll")

pa = GetProcAddress(lb, "compress")

CallWindowProc pa, Me.hWnd, "Hello !", ByVal 0&, ByVal 0&

FreeLibrary lb
End Sub

[Mephy]

Replace private with public if those are in modules
Edit:
i think i misunderstood you

[abazabam]

That's not the problem. Whenever I try to run the code, VB crashes.