Is there a list of supported architectures?
libjf is free software developed on a voluntary basis: the concept of "supported" is not proper.
libjf project keeps track of environments successfully tested: if your system is in that list, you should not encounter big issues; if libjf has never been tested in an environment similar to your one, there might be a bit of porting job to be performed. The track of stress tested environments is hosted at libjf official site: http://libjf.sourceforge.net/
libjf is currently developed on SuSE Linux operating system (SuSE Linux Professional 9.2): the closest to this environment the fewest problems you should have.