I am in the Try It Out that begins on page 129. When I try to complete step 5, my code looks like this:

Private Sub LoadListBox()
        Dim PersonListAdapter As New _PO_DataDataSetTableAdapters.PersonTableAdapter
        Dim PersonListTable As New _PO_DataDataSet.PersonDataTable
        PersonListAdapter.Fill(PersonListTable)
        With lstPersons
            .Items.Clear()
            .DisplayMember = "DisplayName"
            For Each CurrentRow As _PO_DataDataSet.PersonRow In PersonListTable.Rows
                Dim CurrentPerson As New Person(CurrentRow.NameFirst, CurrentRow.NameLast)
                CurrentPerson.ID = CurrentRow.ID
                .Items.Add(CurrentPerson)
            Next
        End With
    End Sub

I am a little unsure, but I believe that is exactly what the book instructs me to do. When I try to run the program, clicking the "Show List" button produces the lstPersons panel, but it is empty, and then VB errors out with this message:

"Items collection cannot be modified when the DataSource property is set."

The offending line of code is ".Items.Clear()", but even when I delete that line, I get the same error message for ".Items.Add(CurrentPerson)". It seems like declaring PersonListAdapter and PersonListTable in the same subroutine is causing this problem, but from the book, I don't know where that bit of code goes.

Please help!!!

Did you do everything in Step 1 of that Try It Out?

The errors you're describing indicate that your DataSource property is still set, but the step says to reset the DataSource property to None as stated in the following paragraph:

Return to the Personal Organizer project you’ve been working on in this chapter. Because you’re going to do everything in code, open the PersonList.vb user control in Design view and select the lstPersons component. Locate the DataSource property and change it to None so that it no longer uses the BindingSource object to retrieve information from the database.

Hope that helps!
Andrew