NRPE: Unable to read output

Hello

thanks for the check, it works locally on my Solaris10 box also for the nagios user without sudo configurations, so I updated my nrpe.cfg with a line like:
command[check_zfs_pools]=/opt/csw/libexec/nagios-plugins/check_zfs.pl -p

but Nagios side when it doesn’t work:
[root@t3nagios ~]# /opt/nagios-plugins/lib/nagios/plugins/check_nrpe -H t3fs11 -c check_zfs_pools
NRPE: Unable to read output

please some clues ?

many thanks,
fabio