rbkconfig_compiler4: 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/rbkconfig_compiler4 - from package: ruby-kde4

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

Error in other languages:
rbkconfig_compiler4: bevel nie gevind nie
rbkconfig_compiler4: comandă negăsită
rbkconfig_compiler4: comando não encontrado
rbkconfig_compiler4: commande introuvable
rbkconfig_compiler4: command not found
rbkconfig_compiler4: käsku ei ole
rbkconfig_compiler4: không tìm thấy lệnh
rbkconfig_compiler4: komanda nerasta
rbkconfig_compiler4: Kommando nicht gefunden.
rbkconfig_compiler4: kommandot finns inte
rbkconfig_compiler4: komut yok
rbkconfig_compiler4: nie znaleziono polecenia
rbkconfig_compiler4: níor aimsíodh an t-ordú
rbkconfig_compiler4: no se encontró la orden
rbkconfig_compiler4: no s'ha trobat l'ordre
rbkconfig_compiler4: opdracht niet gevonden
rbkconfig_compiler4: parancs nem található
rbkconfig_compiler4: perintah tidak ditemukan
rbkconfig_compiler4: príkaz nenájdený
rbkconfig_compiler4: příkaz nenalezen
rbkconfig_compiler4: команда не найдена
rbkconfig_compiler4: командата не е открита
rbkconfig_compiler4: 命令找不到
rbkconfig_compiler4: コマンドが見つかりません