/chkrootkit: line 295: ss: command not found

Not sure where I post this, I have searched on line and talked with hosting company. I've had no success in fixing this issue. Please advise. I receive these emails Cron (cd /usr/local/src/chkrootkit; ./chkrootkit | mail -s " ChkRoot Output" validEmailAddress) with several lines like this. ./chkrootkit: line 2533: ss: command not found ./chkrootkit: line 295: ss: command not found ./chkrootkit: line 295: ss: command not found Immediately followed by a second email Cron (/usr/local/bin/rkhunter -c --nocolors --createlogfile --skip-keypress | mail -s " RkHunter Output" validemailaddress) /bin/sh: /usr/local/bin/rkhunter: No such file or directory Null message body; hope that's ok Thank you.