Run-time error 57121

Experts,
My workbook was created in 2010 and needs to run under 2003. There are some macros in the workbook. When I open it in 2003 it goes through a conversion and then pops up:
Run-time error 57121
Application-defined or object defined error and debugs at the With state:

Sub Workbook_Open()
Dim ws As Worksheet
With Sheets("Home").OLEObjects("cboSelectSpreadsheet").Object
    .Clear
    For Each ws In ThisWorkbook.Worksheets
        If ws.Name <> "Home" Then .AddItem ws.Name
    Next ws
End With

End Sub

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This workbook works fine in 2010 but the users use 2003