There is no need to make this post a sticky as the steps outlined do not make a lick of difference in whether or not you can install multiple party skins. I know because I authored the original post.
The Original
Post was developed as an experiment back in February. Party had recently forced an upgrade which scanned your system for other skins - preventing you from opening a new account if another skin's software was detected.
People were trying various things to circumvent the detection. I attempted to install Empire on a machine where Party was already installed. I used some of the tips and tricks pulled out of the zoo and expanded on them. It worked for some (myself included) however did not work for most others.
It is highly unlikely that any of the steps in this guide have anything to do with whether or not you will be able to apply another skin on the same computer.
The simple solution is to install from a clean computer - this will work 100% of the time. Go to a library, your girlfriend's house, whatever works for you....
Making this post a sticky won't help anyone as it will only mislead and cause people to waste a lot of their time. Time to let it die an honorable death.