call 函数未定义，是否格式不对

我想用音频波形转换频谱，已经做了模 kkfft.bas
在调用时出错，不明白，请指导，谢谢。
Private Sub Timer2_Timer()
  Dim value As Integer, i As Integer
  Randomize
  value = Int(200 * Rnd + (-100))
  List1.AddItem value
  If List1.ListCount > 0 And (List1.ListCount Mod 128 = 0) Then
    Picture1.Cls
    For i = List1.ListCount - 128 To List1.ListCount - 1
      xr(128 - (List1.ListCount - i)) = Val(List1.List(i))
      xi(128 - (List1.ListCount - i)) = 0
    Next
    'FFT变换
  ' Call kkfft0(pr(), pi(), 128, 1) '出错处---函数未定义
    '绘图
    Picture1.Scale (0, 100)-(127, -100)
    Picture1.DrawWidth = 1
    For i = 0 To 127
      Picture1.Line (i, Abs(xr(i)))-(i + 1, Abs(xr(i + 1))), vbBlue
    Next i
  End If
End Sub
---------------------
以下为call 的fftt.bas 的前面部分。
Public Sub kkfft(ByRef pr() As Double, _
    ByRef pi() As Double, _
    ByRef fr() As Double, _
    ByRef fi() As Double, _
    ByVal n As Integer, _
    ByVal k As Integer, ByVal L As Integer)
 
    Dim it As Integer
    Dim m As Integer
    Dim iis As Integer
    Dim i As Integer
    Dim j As Integer
    Dim nv As Integer
    Dim l0 As Integer
   
    Dim p, q, s, vr, vi, poddr, poddi As Double
    For it = 0 To n - 1
        m = it
        iis = 0
        For i = 0 To k - 1
            j = Int(m / 2)
            iis = 2 * iis + (m - 2 * j)
            m = j
        Next
        fr(it) = pr(iis)
        fi(it) = pi(iis)
    Next。。。。。。。。