fs-uae-device-helper: 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/fs-uae-device-helper - from package: fs-uae

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

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