Unzipping the Linux distribution offered on the website works well so long as the shell script is always called from within the PCGen directory itself.
It fails, however, if one does the following (or similar):
This is because the final line of the script reads:
I've made it work through a symlink by placing the following line directly before it:
Which, should the script be called from anywhere, will change into the directory where the script actually lives.
This is more standard behavior for GNU/Linux programs, but if You are targeting Unix as well You may not wish to rely on GNU coreutils like I have in the solution... But I think some kind of change would be good and fairly trivial to implement.
Slackware Linux 14.2 using the zipfile distribution.