Okay, I updated our freebsd installer script to be user/group aware.
Try this and LMK if it works:
pw groupadd -n admin -g 1000
pw groupmod admin -m channels
cd /usr/local
mkdir -p channels-dvr
chown -R channels:channels channels-dvr
curl -f -s https://getchannels.com/dvr/setup.sh | su channels env DOWNLOAD_ONLY=1 sh
sysrc channels_dvr_user=channels
sysrc channels_dvr_group=admin
curl -f -s https://getchannels.com/dvr/install-freebsd.sh | sh