Just run the installer I wrote for OpenSI (attached) and you are all set.
In addition to Tomcat you'll need MySQL.
Installer downloads and sets OpenSI server and client for Firefox and/or xulrunner (I'm an OpenSI user for my company, epsm).
But about the needed versions read this warning
PS Beware that the community version is abandonware. I still use it but it's not maintained anymore.