child_setup: 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/lib64/erlang/erts-5.8.5/bin/child_setup - from package: erlang-erts

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

On Debian possible default full paths are:

/usr/lib/erlang/erts-6.2/bin/child_setup - from package: erlang-base-hipe
/usr/lib/erlang/erts-6.2/bin/child_setup - from package: erlang-base
/usr/lib/debug/usr/lib/erlang/erts-6.2/bin/child_setup - from package: erlang-dbg

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

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