The current version of the plugin is intended for use with Katana versions 3.0 and greater. It will not work with earlier versions of Katana due to a restructuring of Katana's renderer plug-in framework.
RenderMan for Katana (RfK) can either be installed in one of two ways:
See the RenderMan Installation and Licensing documentation for a more detailed explanation.
For Katana 3.0, if you have 3Delight installed, you'll need to set your DEFAULT_RENDERER environment variable to prman or change the renderer parameter in RenderSettings to prman.