zh: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/var/spool/hylafax/bin/dict/zh - from package: hylafax+

You may install the required package with command yum install {package}

Error in other languages:
zh: bevel nie gevind nie
zh: comandă negăsită
zh: comando não encontrado
zh: commande introuvable
zh: command not found
zh: käsku ei ole
zh: không tìm thấy lệnh
zh: komanda nerasta
zh: Kommando nicht gefunden.
zh: kommandot finns inte
zh: komut yok
zh: nie znaleziono polecenia
zh: níor aimsíodh an t-ordú
zh: no se encontró la orden
zh: no s'ha trobat l'ordre
zh: opdracht niet gevonden
zh: parancs nem található
zh: perintah tidak ditemukan
zh: príkaz nenájdený
zh: příkaz nenalezen
zh: команда не найдена
zh: командата не е открита
zh: 命令找不到
zh: コマンドが見つかりません