SharePoint: Child Sites Not Displaying in Menu

[John Powell]

I followed the instructions and have the following in my master page:

<telerik:RadTabStrip runat="server" ID="RadTabStrip1" DataSourceID="siteMapDataSource1" Skin="Office2007" OnClientLoad="SetSearchBoxLoc"/>  
                                    <PublishingNavigation:PortalSiteMapDataSource ID="siteMapDataSource1" Runat="server" 
                                                SiteMapProvider="CombinedNavSiteMapProvider" EnableViewState="true" 
                                                StartFromCurrentNode="true" StartingNodeOffset="0" ShowStartingNode="false" 
                                                TreatStartingNodeAsCurrent="false" TrimNonCurrentTypes="Heading"/> 

However, the tabs are not showing the child sites as drop downs and as I drill into the site, the tabs begin to stack up.

What am I doing wrong?