state “Unknown” for consumables in nagios web interface

Hello, first thank you for this plugin it’s right the plugin I was searching.
But i’ve a problem for consumables. When i do :
./check_snmp_printer -H 127.0.0.1 -C public -t consummable -o black -w 85 -c 90
it return me : Utilisation of the black cartridge : 31% | cons_used=31;85;90;0
So i think it works in command lines but when i go on nagios web interface it writes me “Service State : unknown” for all consumables (not for pages)
Here is a part of my printer.cfg file :
define service {
host_name Wolf-P01/INFORMATIQUE, Workcentre Color 550/ENTRE MARKETING ET ACHAT
use generic-service
service_description Black
check_command check_snmp_printer_consummable!public!black!90!95
}
So i don’t know from where it can come.

Thank you for the answer and sorry for my bad english (i’m french).