erl: command not found

Have You tried accessing the binary with the full path?

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/erl - from package: erlang-erts
/usr/lib64/erlang/bin/erl - from package: erlang-erts
/usr/lib64/erlang/erts-5.8.5/bin/erl - from package: erlang-erts

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

On Debian possible default full paths are:

/usr/bin/erl - from package: erlang-base-hipe
/usr/lib/erlang/bin/erl - from package: erlang-base-hipe
/usr/lib/erlang/erts-6.2/bin/erl - from package: erlang-base-hipe
/usr/bin/erl - from package: erlang-base
/usr/lib/erlang/bin/erl - from package: erlang-base
/usr/lib/erlang/erts-6.2/bin/erl - from package: erlang-base

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