Hi Stafano, I'm not sure the 'loading additional FEFF paths' issue is an installation problem. But for what it's worth here's what I recommend as a 'source install' on Mac OS X, assuming you have a machine with a fast internet connection: 0. install fink and fink's g77 and wget. 1. install the Ifeffit binary from ifeffit-1.2.5a_Mac10.3.dmg. This step is to install PGPLOT correctly: the problem in question is not with PGPLOT. 2. install Perl/Tk from source: 2.1 download Tk-804.027.tar.gz from a CPAN site ~> wget http://www.cpan.org/modules/by-authors/id/NI-S/Tk-804.027.tar.gz 2.2 unpack Tk-804.027 ~> tar xvzf Tk-804.027.tar.gz 2.3 change line 2809 of pTk/mTk/tixGeneric/tixHList.c from '#if 0' to '#if 1' 2.4 build Perl/Tk: ~>perl Makefile.PL ; make 2.5 install Perl/Tk ~>sudo make install 3. install ifeffit from source: 3.1 download: ~>wget http://cars9.uchicago.edu/ifeffit/src/ifeffit-1.2.5.tar.gz 3.2 unpack: ~>tar xvzf ifeffit-1.2.5.tar.gz 3.3 configure ~>./configure --prefix=/Applications/Ifeffit 3.4 build ~> make 3.5 install ~> sudo make install 4. install horae 4.1 set up to use ifeffit: ~>. /Applications/Ifeffit/bin/iff_init.sh if you're using bash and ~>source /Applications/Ifeffit/bin/iff_init.csh if you're using csh or tcsh (if you don't know which shell you're using, try both and whichever complains is the wrong one!) 4.2 install horae ~>horae_update --force Hope that helps. --Matt