Hi,
I have been having nothing but issues attempting to update my game.
I will offer you a few snippets of advice.
Sometimes it is just best to manually uninstall the game, remember to always save a copy of your registry as it details in the guide. Reboot you PC after unistalling.
I would then ensure that your video card is completely up to date.
There is an awesome program out there called CCleaner, it is completely free it will delete all your temp files from locations that you may not even know about. It also has a registry cleaner function too. I would download that and run both elements before running a defrag, now the company that has CCleaner for absolutely free also has a defraggler so if you are running a system such as Vista you will be able to see the defrag process much clearer.
Once you have done this reinstall much like in the guide, I found that each expansion pack updates the base game and those before, so you should only have to worry about the latest patch.
I am steering clear of the Late night patch until they have patched the patch lol
I hope this help