hp-pkservice: 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

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-pkservice - from package: hplip

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