I experienced exactly the same problem: the very same segmentation fault described earlier by mrskhris...
Ubuntu 14.04.3 LTS
apache2: 2.4.7-1ubuntu4.6
php5: 5.5.9+dfsg-1ubuntu4.12
libapache2-mod-php5: 5.5.9+dfsg-1ubuntu4.12
Restarting the Apache server (sudo service apache2 restart) helps for a while, but after a few Zenphoto page calls the error re-occurs and Apache2 has to be restarted yet again. Of course this is no solution, but at least this workaround will at least get your through the setup routine.
No idea where this is coming from. There's some weird interplay between Apache, PHP and Zenphoto... note that I have never experienced such a problem with any other PHP framework on this very server.