Overcoming runtime error Type13 mismatch with #N/A in cell

Hi All

How can i overcome above error when trying to store unique values...Code thanks to Bakerman2

Option Explicit
Sub Unique_Extract()
Dim sn, x0, i As Long
With Sheet1
    sn = .Range("A2", .Range("A" & Rows.Count).End(xlUp))
    With CreateObject("scripting.dictionary")
        For i = 1 To UBound(sn)
            If sn(i, 1) = "" Or sn(i, 1) = "#N/A" Then GoTo nxt1
            x0 = .Item(sn(i, 1))
nxt1:
        Next i
        Sheet1.Range("B2").Resize(.Count) = Application.Transpose(.keys)
    End With
End With
End Sub