lou_checktable: 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_checktable - from package: liblouis-bin

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

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