busybox: 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:

/sbin/busybox - from package: busybox

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

On Debian possible default full paths are:

/bin/busybox - from package: busybox
/bin/busybox - from package: busybox-static

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

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