Perple_X, as usual, is changing. As a result the current sources are inconsistent. The last consistent set of sources (for Perple_X '05) is available at www.perplex.ethz.ch/perplex/ibm_and_mac_archives/old_perplex/Perple_X_05/perp_sources.zip If you wish to compile a more recent version of any Perple_X program please contact me and I will provide the current sources.