kslideshow.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/kslideshow.kss - from package: kscreensaver

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