a2p: 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/a2p - from package: perl

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

On Debian possible default full paths are:

/usr/bin/a2p - from package: perl

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

Error in other languages:
a2p: bevel nie gevind nie
a2p: comandă negăsită
a2p: comando não encontrado
a2p: commande introuvable
a2p: command not found
a2p: käsku ei ole
a2p: không tìm thấy lệnh
a2p: komanda nerasta
a2p: Kommando nicht gefunden.
a2p: kommandot finns inte
a2p: komut yok
a2p: nie znaleziono polecenia
a2p: níor aimsíodh an t-ordú
a2p: no se encontró la orden
a2p: no s'ha trobat l'ordre
a2p: opdracht niet gevonden
a2p: parancs nem található
a2p: perintah tidak ditemukan
a2p: príkaz nenájdený
a2p: příkaz nenalezen
a2p: команда не найдена
a2p: командата не е открита
a2p: 命令找不到
a2p: コマンドが見つかりません