If you can share the URL, we would appreciate. It's weird that you get punished if you don't spam or hide links or copy articles. Maybe some experts here can figure it out for you
Here are some Google threads referring to the same issue... May be you can find the reason in these threads. http://www.google.com/support/forum/p/Webmasters/thread?tid=7151087279bde243&hl=en http://www.google.com/support/forum/p/Webmasters/thread?tid=1f88ec00f8837e03&hl=en