The above example only works for doing relational tables.... and probably like you was not much help. Below is how I used a single hierarchical structured table to build the Tree control.

Step1: Declare a publicly accessable DataTable to be used by the funcitons.
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DataSet NavListDS = new DataSet();

 

Step2: Add the calls to bind the treview on the first pageview. Note the ID of your UltraWebTree goes here.
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    protected void page_load(object sender, EventArgs e)
    {
        if (!Page.IsPostBack)
        {
            // first load DataSet
            LoadDataSet();
            // Build using 0 as the Root ID(Root=0 in DB)
            BuildMenu(UltraWebTree1.Nodes, 0);
        }
    }

 

 

Step3: Add the Functions
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    #region UltraWebTree Builder
    protected void LoadDataSet()
    {
        //Custom Query (I actually use the ObjectDataSource and Fill a datatable, but wanted to show ease of use here...)
       //pull your connection string from Web.Config
       String conn = WebConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
        //Select your NodesID, Text(name), and parent node from the table(mine is called NavList)
       String strSQL = "SELECT NodeId, Name, ParentNode FROM [NavList]";
        SqlDataAdapter myAdapter = new SqlDataAdapter(strSQL, conn);
        //Fill that DataSet we created up top in Step1
        myAdapter.Fill(NavListDS, "NavList");
    }

    private void BuildMenu(Infragistics.WebUI.UltraWebNavigator.Nodes nodes, Int32 IntParent)
    {
        Int32 ThisID;
        String ThisName;
       // Pull the NavList Table from the Dataset and filter it down to get just the nodes we are looking for.
       // NOTE  ParentNode is the name of your parent node column in your database
       DataRow[ children = NavListDS.Tables["NavList"].Select("ParentNode='" + IntParent + "'");
       //no child nodes, exit function
        if (children.Length == 0) return;
        foreach (DataRow child in children)
        {
            // step 1, get the Node's ID
            ThisID = Convert.ToInt32(child.ItemArray[0]);
            // step 2 get the Nodes Text
           ThisName = Convert.ToString(child.ItemArray[1]);
            // step 3
            Infragistics.WebUI.UltraWebNavigator.Node NewNode = new Infragistics.WebUI.UltraWebNavigator.Node();
            NewNode.Text = ThisName;
            NewNode.DataKey = ThisID;
            // step 4
            nodes.Add(NewNode);
            // step 5
            BuildMenu(NewNode.Nodes, ThisID);
        }
    }
    #endregion

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 Good Luck ! 

See Infragistics Example Below:
You can also get to this by going to http://samples.infragistics.com
:)

        Private Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load
            WebPanel2.Visible = WebSamplesVB.Config.ShowDescription

            ' Put user code to initialize the page here
            If Not Me.IsPostBack Then
                ' Get Database connection path for nwind.mdb
                oleDbConnection1.ConnectionString = WebSamplesVB.Config.NorthwindMDBConnString

                customersAdapter.Fill(dataSet11, "Customers")
                ordersAdapter.Fill(dataSet11, "Orders")
                orderDetailsAdapter.Fill(dataSet11, "Order Details")

                Try
                    dataSet11.Relations.Add("CustOrders", dataSet11.Tables("Customers").Columns("CustomerID"), dataSet11.Tables("Orders").Columns("CustomerID"))
                Catch x As System.Exception
                    Dim s As String = x.Message
                    Label1.Text = x.Message
                End Try

                Try
                    dataSet11.Relations.Add("OrderDetails", dataSet11.Tables("Orders").Columns("OrderID"), dataSet11.Tables("Order Details").Columns("OrderID"))
                Catch x As System.Exception
                    Label1.Text = x.Message
                End Try
                Me.UltraWebTree1.DataSource = dataSet11
                Me.UltraWebTree1.Levels(0).LevelKeyField = "CompanyName,CustomerID"
                Me.UltraWebTree1.Levels(2).LevelKeyField = "OrderID,ProductID"

                Me.UltraWebTree1.Levels(0).RelationName = "CustOrders"
                Me.UltraWebTree1.Levels(0).ColumnName = "CompanyName"
                Me.UltraWebTree1.Levels(1).RelationName = "OrderDetails"
                Me.UltraWebTree1.Levels(1).ColumnName = "OrderId"
                Me.UltraWebTree1.Levels(2).ColumnName = "ProductId"
                Me.UltraWebTree1.DataMember = "Customers"
                Me.UltraWebTree1.DataBind()
            End If

        End Sub 'Page_Load