[Samba] Simple question - Machine / User relationsip

[Jim]

Can someone explain to me the mechanizm that Samba uses to relate 
Machines to Users?  I am trying to set up a Samba-LDAP PDC and it seems 
to work OK but I get "No mapping between account names and security IDs 
was done."   This would seem to be a simple user/group 
ownership/permissions thing.  Now I have the following potentially 
pertinent ou's:

People
Computers
Groups

One would think that simply adding a group or having People become 
members of a group would fix the problem.  What fields should I be 
looking at though? Where is this theoretical reltionship stored?

Jim C.