This is ancient software, written in the days of Mac OS 8. Needless to say, Mac OS X is a powerful, modern UNIX system. If you need to deal with RPM files, just install
MacRPM Utilities is a suite of applications for Classic Mac OS to get information about and extract files from Red Hat Package Manager files. It was written with dual Linux/MacOS users in mind.
The MacRPM application can currently display information about RPM packages and extract the gzipped CPIO archives from the packages.
Requires MacOS 8.1 or later. Source code and artwork are released under the terms of the GNU General Public License.