Broken UDF After Upgrade To 2007

Function MultLookup(Rng As Range, lookup_value As String, col_offset As Integer, Optional num_return As Integer) As Variant
Dim myArray(), cnt, cell
For Each cell In Rng
If cell.Value = lookup_value Then
cnt = cnt + 1
ReDim Preserve myArray(1 To cnt)
myArray(cnt) = cell.Offset(0, col_offset).Value
End If
Next cell

If num_return = 0 Then
For i = 1 To cnt
If i = 1 Then
MultLookup = myArray(i)
Else
MultLookup = MultLookup & ", " & myArray(i)
End If
Next i
ElseIf num_return > 0 And num_return