brltty-install: 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:

/bin/brltty-install - from package: brltty

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

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