entry modify failed while trying to change user password

[Kris Vassallo <kris@linuxcertified.com>]

Hello, I am having some problems with users being able to change their
own passwords on the LDAP server. The result comes back with
"implementation specific error 80" so I assume this means I setup
something incorrectly, but I don't know what. Below is the error, below
that is the security section of my slapd.conf file. 

ldappasswd -xSWD "uid=kris,ou=people,dc=xxxxxxxx,dc=com"
New password:
Re-enter new password:
Enter LDAP Password:
Result: Internal (implementation specific) error (80)
Additional info: entry modify failed

--
<slapd.conf security section>

access to *
        by * read
access to attrs=userPassword
        by self write
        by * auth

Can anyone help me out with what I am doing wrong? 

Thanks, 
-Kris