hp-hpdio: command not found

Have You tried accessing the binary with the full path?

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/hp-hpdio - from package: hplip

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