kpendulum.kss: 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/kpendulum.kss - from package: kscreensaver

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