error filling dataset during load event

I am new to asp.net and I'm trying to build my first web page, but when I try to fill a dataset at the page load event I get an error:

object reference not set to instance of object.

Am I missing something? I've done this many times in vb.net. I can't figure out how to step through my code like I do when I'm creating a desktop app, so I don't know exactly where it's failing. I like to be able to see the values of things as it goes through the code.

Code:

---

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        Label2.Visible = False

        Dim dsCheckExisting As New System.Data.DataSet()
        dsCheckExisting.Clear()
        Dim adLookup As New OleDb.OleDbDataAdapter
        adLookup.SelectCommand = New OleDb.OleDbCommand
        Dim cnxAd As New OleDb.OleDbConnection
        cnxAd.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & Chr(34) & "C:\xxx\db1.mdb" & Chr(34) & ""
        Dim joe As String = "OCYNFC005679699.994/21/20125/5/2012"

        With adLookup.SelectCommand
            .Connection = cnxAd
            .CommandText = "select * from sheet1 where [unique]=" & joe & ""
            .CommandType = CommandType.Text

        End With
        Try
            cnxAd.Open()
            adLookup.Fill(dsCheckExisting, "sheet1")
            cnxAd.Close()
        Catch ex As Exception
            cnxAd.Close()

        End Try
        Dim dr As DataRow
        If dsCheckExisting.Tables("sheet1").Rows.Count > 0 Then
            For Each dr In dsCheckExisting.Tables("sheet1").Rows
                Label1.Text = dr("booked")
            Next
        End If
     
    End Sub

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First of all put your code inside "If Not Page.IsPostBack Then". You must also know that your dataset will regenerate after every postback thus you will loose all your data(and must store it if you want to keep it). This is a big difference when programming in asp.net because the web is stateless.

Ok. I finally got the correct error and it says:

ex = {"The 'Microsoft.Jet.OLEDB.4.0' provider is not registered on the local machine."}

I have microsoft access loaded and activated on this machine, so I don't understand the error message.

Any clues? Also, I've used this code many times before on this machine and only now has it given me this error.