Are you trying to update Openldap global or config database configuration? Getting insufficient access error (50)?
So, What is the BIND dn (i.e username) you are using? The error simply says that BIND dn authentication successful but it does not have write access to database you are trying to modify.
# ldapmodify –axw ppsswwdd -D "cn=manager,dc=sunt,dc=com" -f db.ldif modifying entry "olcDatabase={2}bdb,cn=config" ldap_modify: Insufficient access (50)