qtoctave-info-reader: 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/qtoctave-info-reader - from package: qtoctave

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

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