echo: 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:

/bin/echo - from package: coreutils

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

On Debian possible default full paths are:

/bin/echo - from package: coreutils
/usr/lib/plan9/bin/echo - from package: 9base

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

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