qscan: 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/qscan - from package: qpxtool

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

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