Use Listbox Contents To Populate A Scripting Dictionary

Can I use my listbox contents to populate a scripting dictionary?

Dim a, z As Long
Set dic = CreateObject("scripting.dictionary")
With Sheets("Changes")
a = ListBox1.List
'a = .Range("b1", .Range("b" & Rows.Count).End(xlUp)).Offset(, -1).Resize(, 10).Value
End With

For z = 2 To UBound(a, 1)
If Not dic.exists(a(z, 2)) Then
ReDim w(1 To 10, 1 To 1)
For zz = 1 To 10: w(zz, 1) = a(z, zz): Next
dic.Add a(z, 2), w
Else
w = dic(a(z, 2))
ReDim Preserve w(1 To 10, 1 To UBound(w, 2) + 1)
For zz = 1 To 10: w(zz, UBound(w, 2)) = a(z, zz): Next
dic(a(z, 2)) = w
End If
Next
ComboBox2.List = dic.keys
ComboBox2.Value = Sheets("Calendar").Range("E3").Value
This code doesn't work because the bold line falls over.... the Remmed statement below it works fine though...