rmadison: 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
/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/rmadison - from package: devscripts

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