The file /home/tc/.fluff.conf can have inside it a parameter (it has in my configuration): FollowLinks=0
So maybe this means that fluff first reads its configuration to see if it needs to use the external script fluf_fc.sh, by default is not. Of course fluff (preventive) cry if script is not found, even if not need it (because busybox/du -L => Follow all links is not invoked).