kuiviewer: 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/kuiviewer - from package: kdesdk

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

On Debian possible default full paths are:

/usr/bin/kuiviewer - from package: kuiviewer

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

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