oggSlideshow: 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/oggSlideshow - from package: oggvideotools

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

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