showing “null”value

My command.cfg

define command{
command_name check_hddtemp_socket.pl
command_line $USER1$/check_hddtemp_socket.pl -H $HOSTADDRESS$ -p $ARG1$ $ARG2$
}

My localhost.cfg

define service{
use local-service ; Name of service template to use
host_name localhost
service_description Hard Disk Temperature Socket
check_command check_hddtemp_socket.pl!40!50
notifications_enabled 0
}

Nagios is giving “null” value in “Web Interface”.