Every time World of Warcraft does a patch/update it will reinstall the wow64.exe file on your system (if you have a 64bit system)....so, you'll need to go into your WOW folder and either rename or delete the wow64.exe file. Even if you have the 32bit checked it will not load and the 64bit will override unless you remove/change that file name. Your log shows that there isn't an instance of WOW open, so you either haven't opened up WOW first or the above is the issue.
I deleted the 64 bit client, but I'm getting the same issue. I always get this error when I patch now. http://puu.sh/5JI9i.png I've tried with wow open, wow closed, have deleted 64 bit client...