List box population that does not seem to happen

So I have just tried and using the following code - works

As a module wide variable
Dim adatearray(1 To 31, 1 To 3) As Variant

In the initialize
For I = 1 To 31
    adatearray(I, 1) = I
Next I
For I = 1 To 12
    adatearray(I, 2) = Worksheets(WS3nam).Cells(I + 2, 2)
Next I
For I = 1 To 4
    adatearray(I, 3) = Year(Now) - 2 + I
Next I

in the ok button sub
Adate = adatearray(ListBox5.ListIndex + 1, 1) & "-" & adatearray(ListBox6.ListIndex + 1, 2) & "-" & adatearray(ListBox7.ListIndex + 1, 3)

Thanks again for your help