argus_linux: 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

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/sbin/argus_linux - from package: argus-server

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