Yes, the online README file is definitely out of date. I’ll see if we can get that updated today, so that others don’t have to deal with the same hassles that you had. FWIW, I tested installation on a 12.04 64-bit Ubuntu system using Kevin’s instructions for Oracle Java 7 installation and the instructions here to install the Ignition .deb file. The Gateway fired right up for me, so installing Java 7 via apt is the best way to go.