autoconf2.64: 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 Debian possible default full paths are:

/usr/bin/autoconf2.64 - from package: autoconf2.64

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

Error in other languages:
autoconf2.64: bevel nie gevind nie
autoconf2.64: comandă negăsită
autoconf2.64: comando não encontrado
autoconf2.64: commande introuvable
autoconf2.64: command not found
autoconf2.64: käsku ei ole
autoconf2.64: không tìm thấy lệnh
autoconf2.64: komanda nerasta
autoconf2.64: Kommando nicht gefunden.
autoconf2.64: kommandot finns inte
autoconf2.64: komut yok
autoconf2.64: nie znaleziono polecenia
autoconf2.64: níor aimsíodh an t-ordú
autoconf2.64: no se encontró la orden
autoconf2.64: no s'ha trobat l'ordre
autoconf2.64: opdracht niet gevonden
autoconf2.64: parancs nem található
autoconf2.64: perintah tidak ditemukan
autoconf2.64: príkaz nenájdený
autoconf2.64: příkaz nenalezen
autoconf2.64: команда не найдена
autoconf2.64: командата не е открита
autoconf2.64: 命令找不到
autoconf2.64: コマンドが見つかりません