The Small Business Suite may run on newer versions of those distributions, but those are the only supported Linux platforms according to the docs. You may be able to install SBS on another distribution that supports RPM, but folks running Debian or Slackware are probably out of luck. In addition to one of the supported distros, you need to have a server with a minimum of 256 MB of RAM and a Pentium II running at 400 MHz or faster. IBM Recommends 384 MB of RAM and a 600-MHz processor. If you're going to install most or all of the Suite components, it will take at least three to four hours to install everything, depending on the speed of your machine.
Installation actually takes place in a couple of stages.
The first stage is to install the Suites Installer, which is an RPM package. There's a handy script to handle that. The Suites Installer handles installing software on the local computer and remote clients. If you're going to run any of the software on client computers, you'll need to install the IBM Installation Agent on those as well. Client computers need to have a minimum of 64 MB of RAM and a Pentium II-class processor.