I just dont get it....please help

[ranasrule]

why doesnt this code work ??

Private Sub Command2_Click()
Dim aa As Integer
aa = 1
Dim ad(aa) As String
End Sub

iam in a situation where i have to declare an array that has a size based on a variable....so if the variable value is 1 then the array declared will be of size 1 if the variable value is 2 then the array declared will be of size 2 and so on.....how would i go about achieving this task....any help will be greatly appreciated