I've found the following, which may be of help to other people:

After I've installed the game, following this guide (with the exeption of installing to ~/games instead of /opt), the PlaneShift directory is owned by root. The installer recogniser the current user as root, thus effectivly preventing access to the game's folder. A chown -r will solve this problem:
sudo chown -hR <your username> <planeshiftdir>
Another solution might  be to manually set the permissions in the installer, although I haven't tried that myself.

~Vendero