I'm trying to write some code that will take a value WeekNum, and add it to an array Week(1 To 51), and then associate a value from a Textbox TargDef. Once this has been added to the array, I want to look up the value of the array for the previous WeekNum and add it to a value ProdTarg.

I've created this much so far:

Dim Week(1 To 51) Dim Count As Integer

If TargDef < 0 Then
    Count = WeekNum
    Week(Count) = Abs(Val(TargDef))
    If Val(Week((Count) - 1)) = 0 Then
        ProdTarg = Val(ProdTarg)
        Else
        ProdTard = Val(ProdTarg) + Val(Week((Count) - 1))
    End If
End If

I am currently receiving the error "Subscript out of Range" for the line If Val(Week((Count) - 1)) = 0 Then

Any help will be greatly appreciated!