[Samba] Added NT$ machine to SAMBA PDC and got this in the administrators group?

[rod at newtonhall.co.uk]

weird, just created a new machine account via useradd(mandrake 8.2)  and
then logged the NT4 machine into the samba domain, by default "root" or
"admin" was not added to the administrators group, so i logged into the
local machine and added them manually. Spotted this though
under members:

NTGX\unix_group.2147483404??


what's this all about and why did "root" not get added to the
administrators group automatically?

cheers
rod