Hi, a bit of googling solved the problem, this article eplains it, http://www.ghacks.net/2010/10/12/fix-pinned-items-opening-as-new-icons-in-windows-7-taskbar/ it worked for me, so hopefully it'll work for you too.

Thanks, han, that did the trick. I thought I had tried that, but apparently not. Now, I've also noticed that now individual tabs don't show up as thumbnails on the taskbar. I'm pretty sure they did before. I browsed through the bug report for 4.0.1 to see if there was anything indicating they might have been messing with this but found nothing. Oh well, just another Windows mystery I guess. It would be nice if we could see the tabs as thumbnails when mousing over the taskbar - saves time when selecting a browser page. Thanks again for your help.

Your welcome. I don't have that other problem, but I'm pretty sure I saw it mentioned somewhere whilst I was looking for this solution, so you should be able to find the answer somewhere if you google it.