rd2: 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/rd2 - from package: rdtool

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

Error in other languages:
rd2: bevel nie gevind nie
rd2: comandă negăsită
rd2: comando não encontrado
rd2: commande introuvable
rd2: command not found
rd2: käsku ei ole
rd2: không tìm thấy lệnh
rd2: komanda nerasta
rd2: Kommando nicht gefunden.
rd2: kommandot finns inte
rd2: komut yok
rd2: nie znaleziono polecenia
rd2: níor aimsíodh an t-ordú
rd2: no se encontró la orden
rd2: no s'ha trobat l'ordre
rd2: opdracht niet gevonden
rd2: parancs nem található
rd2: perintah tidak ditemukan
rd2: príkaz nenájdený
rd2: příkaz nenalezen
rd2: команда не найдена
rd2: командата не е открита
rd2: 命令找不到
rd2: コマンドが見つかりません