ldapmodify error "entry store failed" "implementation specific"

[Elliot <elliot@ecowizards.com>]

Hello all,
I have what I hope is just a newbie mistake, but which I can't find a  
solution for in the archives or on google.
I have just setup a new LDAP db and can add to it using slapadd, but  
when I try to add the same ldif file with ldapadd or ldapmodify I get  
the following error:

[root@db1 ldapstuff]# ldapmodify -D  
"cn=Manager,dc=mohawkschools,dc=org" -W -x -a -v -f users.ldif
ldap_initialize( <DEFAULT> )
Enter LDAP Password:
add cn:
        Elliot A Anders
add sn:
        Anders
add mail:
        eanders@hawlemont.mtrsd.k12.ma.us
add objectClass:
        inetOrgPerson
adding new entry "cn=Elliot A  
Anders,ou=mtrsd,ou=users,dc=mohawkschools,dc=org"
modify complete
ldap_add: Internal (implementation specific) error (80)
        additional info: entry store failed

It seems odd to me because it says "modify complete" but nothing gets  
modified!
The password is correct, as it gives me an authentication error if I  
enter that incorrectly, and the "entry store failed" error is a bit  
too obtuse for me to start guessing at this point.

Also if anyone can tell me the correct way to quit slapd, I'd love to  
hear it because the method in the book I have doesn't work, and it  
sounds like kill (process number) is not the way to go.

Thanks for your time,
Elliot

This is running on Fedora Core 4
Openldap 2.2.23-5
cyrus-sasl 2.1.20-5
openssl 0.9.7f-7
db4 4.3.27-3  (from sleepycat)

#/etc/openldap/slapd.conf
#
# See slapd.conf(5) for details on configuration options.
# This file should NOT be world readable.
#
# Global Section

include         /etc/openldap/schema/core.schema

# Support inetOrgPerson
include         /etc/openldap/schema/cosine.schema
include         /etc/openldap/schema/inetorgperson.schema

# Loggin parameters
loglevel        296
pidfile         /usr/local/var/slapd.pid
argsfile        /usr/local/var/slapd.args

# TLS options for slapd
TLSCipherSuite          HIGH
TLSCertificateFile      /etc/local/slapd-cert.pem
TLSCertificateKeyFile   /etc/local/slapd-key.pem

# Misc security settings
password-hash {SSHA}

# Define the database
database        bdb

# Define the root suffix
suffix          "dc=mohawkschools,dc=org"

# Define the root DN for superuser privs
rootdn          "cn=Manager,dc=mohawkschools,dc=org"

# Define the password
rootpw          {SSHA}SxDEv6AcsCTFphO4P57WQjIvvexCHy3A

# Define the directory containing the db
directory       /var/ldap/mohawkschools.org

# Files should be created rw for owner only
mode            600

# Maintain an index
index           cn,sn,mail              eq,sub
index           objectClass             eq
index           departmentNumber        eq

# DB tuning
cachesize       2000

# Simple ACL read to the world
access to *
        by * write