rsusers: 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/sbin/rsusers - from package: ax25-tools

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

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