Cant Update my Lumia 800

I want to Update my Lumia 800 with Zune (Windows 8) and then it Upgrades till the End and on my Lumia is a Message that tells your Phone is now on the newses Version (or something like that) but then it tells me that there is a New Update and i have to install it again i have done it now 4 times

Can i do something or is it because of Windows 8