plasma-netbook: 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/plasma-netbook - from package: plasma-netbook

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

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