fr: 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/fr - from package: hylafax+

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

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