as_client: 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/as_client - from package: code-aster-gui

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

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