Element is already the child of another element Error on PivotViewerSample

I started to play a little with Pivot Viewer, but unfortunately from the first sample that you can download from http://www.silverlight.net/learn/pivotviewer/  I had an error
"Element is already the child of another element"
After searching the net a little and with no easy solution adder than get the latest version of Silverlight 4 toolkit that unfortunately didn't help , I've started to remove elements from .xaml and .cs
After removing all comments and formatting the Style.xaml I was surprised to observe that everything was working.
So I recommend you to do the same , I don't know what the proablem was but now is working just fine.

Just in case here is another archive with my working example:
http://cid-ec42eac854e5c4c7.office.live.com/self.aspx/.Public/PivotViewerSample.zip