lou_checkhyphens: 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 Debian possible default full paths are:

/usr/bin/lou_checkhyphens - from package: liblouis-bin

You may install the required package with command apt-get install {package}

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