to run pure CS application (like walktest) you need to put right env variable:
unset CRYSTAL
CRYSTAL_CONFIG=/etc/crystalspace
CRYSTAL_PLUGIN=/usr/lib/crystalspace
but to run PS you need to unset them (trouble between vfs.cfg files)
unset CRYSTAL_CONFIG
unset CRYSTAL_PLUGIN
export CRYSTAL=/usr/lib/crystalspace
i'm working on a way to have same env variable for CS & PS
but it's doesn't work for now

env variable are set by emerge crystalspace in /etc/env.d/90crystalspace
loux