add new entry problem

[openldap <openldap@8848.net>]

hi,
   I have added many entries ,now I want to add a new entry to ldap.so I append a dn to original  ldif file .
 how, i use ldapadd and -a options.It always tell me the first entry such as dc=mail,dc=hollybridge,dc=not, "Already exist"
what should i do to add a new entry?
    Thansk for any good ideals.


                  

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