The latest Skyrim patch, which released yesterday on the PlayStation 3 and Xbox 360, has been causing numerous issues since its release.
On the Bethesda forums, players have been reporting that no matter how much protection they equip themselves with, the game will not register them causing you to receive full damage from attacks. Players have also noticed that when encountering dragons, sometimes they will fly backwards.
These both are, of course, major issues and hopefully Bethesda will be able to solve these issues as soon as possible. In the meantime, you may refuse to install the patch, however, you will not be able to play online.
Source: Bethesda Forums