diskscan: 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/diskscan - from package: diskscan

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

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