Permission denied

This is unlikely, but conceivable. For each component of the program, do a long listing, e.g. (with the appropriate install directory)

  ls -l /usr/local/bin/epix

The header and library must be readable, and the shell scripts and directories must be readable and executable. From the install directory, do

chmod 0755  bin  include  lib  bin/{epix,elaps,laps,flix,keywords}
chmod 0644  include/epix.h  lib/libepix.a  man/man1/epix.1

If you still cannot get ePiX to run, please send email to the author. Generally, it is helpful to specify the operating system (e.g., RedHat 8.2, or Debian Potato on a G4 Powerbook), the version of the C compiler (e.g. gcc-3.2), the version of ePiX, and where you downloaded the sources (CTAN, the project home page, etc.). Specific commands you typed and error messages may also be helpful. If you don't know what an error message means, feel free to paste or attach it to your email as plain text. The author does not have access to an enormous variety of systems, and sometimes reported errors never get explained, but to date no error has failed to be worked around.