krubyapplication: 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/krubyapplication - from package: ruby-kde4

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

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