I can't add entries to my OpenLDAP. Please Help.

["Qianfeng" <maxqian@sjtu.edu.cn>]

Title: Message

Dear All, 

I followed the instructions on the "OpenLDAP 2.1 Administrator's Guide" and wrote the following .ldif file. 

        # Organization for Example Corporation
        dn: dc=example,dc=com
        objectClass: dcObject
        objectClass: organization
        dc: example
        o: Example Corporation
        description: The Example Corporation

        # Organizational Role for Directory Manager
        dn: cn=Manager,dc=example,dc=com
        objectClass: organizationalRole
        cn: Manager
        description: Directory Manager

I use the following command to try to add this to my database:

        ldapadd -f entries.ldif -x -D "cn=Manager,dc=example,dc=com" -w secret

However, i always get the followin error:

        ldap_bind: invalid credentials

Any suggestion is welcomed.

Thansks and best Regards,

Max