urxvtcd: 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/urxvtcd - from package: rxvt-unicode-256color
/usr/bin/urxvtcd - from package: rxvt-unicode-lite
/usr/bin/urxvtcd - from package: rxvt-unicode

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