I just recently realized that the pfPortals code is no longer 100% compatible with the most recent version of Performer/IRIX. Thanks to Claudio Silva for bringing this to my attention. Check back in a few days; by the end of SIGGRAPH (July 28) I hope to have pfPortals working on the latest versions of Performer for both IRIX and Linux. In the meantime, if you're still using Performer 2.0, or want to update the library yourself (it shouldn't be hard, just a few minor IRIS GL -> OpenGL conversions and minor Makefile tweaks), feel free to download the current version of pfPortals:

Download the latest version of the library.
Download fltLoader, a Performer library for reading MultiGen 14.2 OpenFlight (tm) files with portal information embedded in the comments.
Download perfport, a simple perfly-based application designed to work with pfPortals and fltLoader.