各位高手帮忙看看这段程序哪里出现问题了

    Private Structure individual '个体
        Public chrom() As Integer
        Public fitness As Double
        Public varible() As Double
        Public Sub initialize()
            ReDim chrom(40)
            ReDim varible(2)
        End Sub
    End Structure
''''''''''''''''''''''''''''''''''
        Dim bianma As String
        popsize = Val(TextBox2.Text)
        chromsize = Val(TextBox1.Text)
        If chromsize Mod 2 <> 0 Then
            chromsize = chromsize + 1
        End If
        For i = 1 To popsize
            currentpop(i) = New individual()
            For j = 1 To chromsize
                currentpop(i).chrom(j) = random(2)''''出现未将对象引用设置到对象实例
            Next
        Next