Are you running 64 bit Ubuntu? Last time I looked, it won't run on 32 bit systems regardless of any efforts you make.
I've put a complete(?) tutorial on using Oracle-xe on 64 bit Ubuntu on
http://www.antikytherapubs.com/ that should get you going. I put this together after attempting to use several other on-line instructions that I couldn't get to work, although I don't believe I'm familiar with the site you mentioned. One difficulty is that Oracle doesn't supply a .deb themselves, and some .deb files built on certain systems don't always contain all the dependencies.
Scroll down that page and you'll see a link to either view or download the Database Design Note for using Oracle on Ubuntu (and other Debian based systems).
A version of this app note was also published in an earlier issue of Full Circle magazine - a free monthly Ubuntu magazine if you're not familiar with it (several years of back issues available if you're just getting started with Ubuntu).
I hope this helps.