Устранить ошибку "sub or function not defined" - VB

Private Sub CommandButton1_Click()
Dim z As String
Dim n As Integer
z = "d:\texnika.txt"
Open z For Input As #1
n = 0
While Not EOF(1)
        With a(n)
     Input #1, .vyd, .rik, .cina, .kolir, .kilkist
     n = n + 1
Wend
End Sub