attribute type undefined

["WR" <gen2@planetofidiots.com>]

Hello,

I'm new to openldap and have read the Administrators guide several times,
plus googled quite a bit, but am unable to discover the solution to the
following problem.

If I run this (as root):

/usr/lib/openldap/slapd -d -1 -u ldap -g ldap -f /etc/openldap/slapd.conf

then set up an example.ldif file as directed (with appropriate local
info), then run (as user)

sudo ldapadd -x -D "cn=Manager,dc=<appropriate local info>,dc=com" -W -f
example.ldif

(sorry for the email linebreak-age)

I get this:

Enter LDAP Password:
adding new entry "dc=<appropriate local info>,dc=com"
ldapadd: update failed: dc=<appropriate local info>,dc=com
ldap_add: Undefined attribute type (17)
        additional info: dn: attribute type undefined


What should I be looking for to discover the problem?

slapd.conf inludes this schema (only this one)

include  /etc/openldap/schema/core.schema

and

database        bdb
suffix          "dc=<appropriate local info>,dc=com"
rootdn          "cn=Manager,dc=<appropriate local info>,dc=com"

(of course <appropriate local info> is replaced with a real domain element)

plus the other normal default stuff

Thanks for any pointers!
WR