krdc_rfb_approver: 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/krdc_rfb_approver - from package: krdc

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

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