strange bug in useradd in potato ?!?

[Oleg Krivosheev <kriol@fnal.gov>]

Hi, All

i'm running potato and just tried to upgrated telnetd to 0.14-1
and this is what i got:

Setting up telnetd (0.14-1) ...
adduser: Warning: The home dir you specified already exists.
Adding system user telnetd...
Adding new group telnetd (101).
Adding new user telnetd (101) with group telnetd.
useradd: unknown group telnetd
adduser: `useradd -d /usr/lib/telnetd -g telnetd -s /bin/false -u 101
telnetd' returned error code 1536.  Aborting.
Cleaning up.
Removing user `telnetd'.
userdel: user telnetd does not exist
Removing group `telnetd'.
groupdel: group telnetd does not exist
dpkg: error processing telnetd (--configure):



Any ideas why useradd died? What error 1536 means?

thank you 

oleg