brltty-ctb: 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/brltty-ctb - from package: brltty

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

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