So I've just started configuring Nagios in my environment and I'm getting the above error when trying to user the NRPE plugin.

The host file is as follows:

define {

    host_name   servername    
    alias       servername
    address     xxx.xxx.xxx.xxx
    use         generic-host    
}

define service {    
    use                     generic-service    
    host_name               servername   
    service_description CPU load    
    check_command           check_nrpe!alias_cpu    
}

This is the check_nrpe.cfg file that is located in /etc/nagios-plugins/config

NOTE: this command runs a program $ARG1$ with arguments $ARG2$

define command {   
        command_name    check_nrpe    
        command_line    /usr/lib/nagios/plugins/check_nrpe -H $HOSTADDRESS$ -c $ARG1$ -a $ARG2$    
}

NOTE: this command runs a program $ARG1$ with no arguments

define command {    
        command_name    check_nrpe_1arg    
        command_line    /usr/lib/nagios/plugins/check_nrpe -H $HOSTADDRESS$ -c $ARG1$    
}

Any ideas what is wrong or where to start to solve this?