autoconf268: 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/autoconf268 - from package: autoconf268

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

Error in other languages:
autoconf268: bevel nie gevind nie
autoconf268: comandă negăsită
autoconf268: comando não encontrado
autoconf268: commande introuvable
autoconf268: command not found
autoconf268: käsku ei ole
autoconf268: không tìm thấy lệnh
autoconf268: komanda nerasta
autoconf268: Kommando nicht gefunden.
autoconf268: kommandot finns inte
autoconf268: komut yok
autoconf268: nie znaleziono polecenia
autoconf268: níor aimsíodh an t-ordú
autoconf268: no se encontró la orden
autoconf268: no s'ha trobat l'ordre
autoconf268: opdracht niet gevonden
autoconf268: parancs nem található
autoconf268: perintah tidak ditemukan
autoconf268: príkaz nenájdený
autoconf268: příkaz nenalezen
autoconf268: команда не найдена
autoconf268: командата не е открита
autoconf268: 命令找不到
autoconf268: コマンドが見つかりません