How to disable insert/delete columns & rows?

Hi,

How do you hide the menu items related to inserting and deleting rows and columns?

I have the following macro, but it only works about half the time and I don't know why. When it doesn't, I get the error:

"Run time error 5: Invalid procedure or call argument" in both xl2003 and 2010.

Sub HideMenuItems()

    With Application.CommandBars("Row")
        .Controls("Insert").Enabled = False
        .Controls("Delete").Enabled = False
    End With

    With Application.CommandBars("Column")
        .Controls("Insert").Enabled = False
        .Controls("Delete").Enabled = False
    End With

    With CommandBars("Worksheet Menu Bar")
        .Controls("Insert").Controls("Rows").Enabled = False
        .Controls("Insert").Controls("Columns").Enabled = False
        .Controls("Insert").Controls("Cells").Enabled = False
        .Controls("Edit").Controls("Delete").Enabled = False
    End With

End Sub

Thanks,

Lawrence