krdc: 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 CentOS possible default full paths are:

/usr/bin/krdc - from package: kdenetwork

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/krdc - from package: krdc

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

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