toobig6: 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/toobig6 - from package: thc-ipv6

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

Error in other languages:
toobig6: bevel nie gevind nie
toobig6: comandă negăsită
toobig6: comando não encontrado
toobig6: commande introuvable
toobig6: command not found
toobig6: käsku ei ole
toobig6: không tìm thấy lệnh
toobig6: komanda nerasta
toobig6: Kommando nicht gefunden.
toobig6: kommandot finns inte
toobig6: komut yok
toobig6: nie znaleziono polecenia
toobig6: níor aimsíodh an t-ordú
toobig6: no se encontró la orden
toobig6: no s'ha trobat l'ordre
toobig6: opdracht niet gevonden
toobig6: parancs nem található
toobig6: perintah tidak ditemukan
toobig6: príkaz nenájdený
toobig6: příkaz nenalezen
toobig6: команда не найдена
toobig6: командата не е открита
toobig6: 命令找不到
toobig6: コマンドが見つかりません