Error import the centreon_clapi_import_commands

Hey brothers,

i am testing to migrate my nagios configuration (version 4.2.1) to centreon (version 2.7.7) wich have already installed in my VM linux ubuntu 16.04 ...
i have follow the instructions in this link: https://documentation-fr.centreon.com/docs/centreon/en/2.8.x/migration/nagiostocentreon.html (= Nagios Reader vers Centreon CLAPI). i have set this command:
perl nagios_reader_to_centreon_clapi.pl --nagios_reader_to_centreon_clapi.pl --config /usr/local/nagios/etc --version 4 > /tmp/centreon_clapi_import_commands.txt:
and then:
/usr/local/centreon/bin/centreon -u admin -p admin -i /tmp/centreon_clapi_import_commands.txt

the command prompt return :

Line 1 : Resource is already tied to instance
Line 2 : Resource is already tied to instance
Line 3 : Resource is already tied to instance
Line 4 : Resource is already tied to instance
Line 5 : Resource is already tied to instance
Line 6 : Resource is already tied to instance
Line 7 : Resource is already tied to instance
Line 8 : Resource is already tied to instance

Is it normal ?
the result is shown in the figures

Thanks in advance.
Best regards : )