rcvxterm: 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/share/doc/mh-book/examples/mh/bin/rcvxterm - from package: mh-book

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

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