about installing RPMS using SuSE try: http://sdb.suse.de/sdb/en/html/ke_rpm.html
about OpenACS 4 RPM install on SuSE, no SuSE RPM exists for OpenACS (yet). You can try Jonathan Marsden's RPM for Redhat (above) and let him know how it works...
Alternately, installing from source-code should provide you with a working system.
-Torben
