ergo: 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/ergo - from package: ergo

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

On Debian possible default full paths are:

/usr/bin/ergo - from package: ergo

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

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