nagios (Last Notification: N/A (notification 0))

I can't figure out but for some reason Nagios doesn't send me an alert on some of the services that I monitor, I was wondering if someone can help me out a bit.

this is service

define service {
    hostgroup_name          nrpe-disk

    service_description     disk
    use             alarm,check
    check_command           check_nrpe1!check_disk
    register            1
    }

here is my command

define command {
       command_name                         check_nrpe1
       command_line                         $USER1$/check_nrpe -H $HOSTADDRESS$ -c $ARG1$
}

here is service template

define service {

       name                                 alarm
       notification_interval                0
       notification_period                  247
       notification_options                 w,u,r,c,f,s
       notifications_enabled                1
       contact_groups                       staff
       register                         0

}

define command {
       command_name                         notify-host-by-email
       command_line                         /usr/bin/printf "%b" "***** Nagios *****\n\nNotification Type: $NOTIFICATIONTYPE$\nHost: $HOSTNAME$\nState: $HOSTSTATE$\nAddress: $HOSTADDRESS$\nInfo: $HOSTOUTPUT$\n\nDate/Time: $LONGDATETIME$\n" | /usr/bin/mail -s "** $NOTIFICATIONTYPE$ Host Alert: $HOSTNAME$ is $HOSTSTATE$ **" $CONTACTEMAIL$
}   

define command {
       command_name                         notify-host-by-pager
       command_line                         /usr/bin/printf "%b" "Notification Type: $NOTIFICATIONTYPE$\nHost: $HOSTNAME$\nState: $HOSTSTATE$\nAddress: $HOSTADDRESS$\nInfo: $HOSTOUTPUT$" | /usr/bin/mail $CONTACTPAGER$

}   

define command {
       command_name                         notify-service-by-email
       command_line                         /usr/bin/printf "%b" "***** Nagios *****\n\nNotification Type: $NOTIFICATIONTYPE$\n\nService: $SERVICEDESC$\nHost: $HOSTALIAS$\nAddress: $HOSTADDRESS$\nState: $SERVICESTATE$\n\nDate/Time: $LONGDATETIME$\n\nAdditional Info:\n\n$SERVICEOUTPUT$" | /usr/bin/mail -s "** $NOTIFICATIONTYPE$ Service Alert: $HOSTALIAS$/$SERVICEDESC$ is $SERVICESTATE$ **" $CONTACTEMAIL$
}   

define command {
       command_name                         notify-service-by-pager
       command_line                         /usr/bin/printf "%b" "Notification Type: $NOTIFICATIONTYPE$\n\nService: $SERVICEDESC$\nHost: $HOSTALIAS$\nAddress: $HOSTADDRESS$\nState: $SERVICESTATE$\n\nAdditional Info:\n\n$SERVICEOUTPUT$" | /usr/bin/mail $CONTACTPAGER$

}   

define contactgroup {
    contactgroup_name                   staff
    alias                               XXXXXXXX
    members                             XXXXXXXX XXXXXXXX
    }   

define contact {
    contact_name                        XXXXXXX XXXXXX
    alias                               XXXXXXXXX
    host_notifications_enabled          1
    service_notifications_enabled       1
    host_notification_period            247
    service_notification_period         247
    host_notification_options           d,u,r,f,s

    service_notification_options        w,u,c,r,f,s
    host_notification_commands          notify-host-by-email,notify-host-by-pager
    service_notification_commands       notify-service-by-email,notify-service-by-pager
    email                               XXXXXXXXX@XXXXXXXX.XXX
    pager                               XXXXXXXXXX@messaging.sprintpcs.com
    }

Answer

I don't see it mentioned in your question or any of the answers but have you checked the nagios.cfg file for the enable_notifications setting? Is it set to 0 or 1?

Also is this only happening on a given service notification or is it affecting all notifications? If it's all I would suspect that enable_notifications is set to 0 in the nagios.cfg file. If so try changing it to 1 and restarting Nagios.