If you use Workgroup Manager to simultaneously promote several users to LDAP directory administrator status, these "batch-promoted" admin users will not be able to change passwords for users that use an Open Directory password. When they try, they will get a -14090 error.
This issue affects Mac OS X Server 10.3 to 10.3.9.
To avoid the issue, promote only one user at a time to administrator status. If you want to verify whether a promoted admin user will be able to change Open Directory user passwords, execute this command in Terminal, where newadmin is the short name of the admin user being verified:
pwpolicy -u newadmin -getpolicy | awk '{print $2}'
If you get a result of isAdminUser=1, that admin user can change passwords. If the result is isAdminUser=0, demote and then repromote the user in Workgroup Manager. Alternatively, you could use the pwpolicy command to set the isAdminUser attribute to 1.