brltty-trtxt: 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-trtxt - from package: brltty

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

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