[Dev] Cron jobs aren't running on repo and `su' is broken!!

[Joseph Graham]

repo user's hourly `make_repo_torrents' is not getting run and neither 
is one of pbot-ng's crons. Also, su is broken!!:

# su - repo
bash: /bin/su: No such file or directory

If anyone has trouble getting root access to fix it, I have a screen 
session with a root terminal in it. I've enabled multiuser mode and 
granted access to lukeshu,fauno and mtjm. I've never used screen 
multiuser mode before but obviously it's documented by info screen.