kdeasciiquarium.kss: 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 CentOS possible default full paths are:

/usr/bin/kdeasciiquarium.kss - from package: kdeartwork-screensavers

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/kdeasciiquarium.kss - from package: kscreensaver

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

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