usbrelay: 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/usbrelay - from package: usbrelay

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

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