kded4: 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/kded4 - from package: kdelibs

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

On Debian possible default full paths are:

/usr/bin/kded4 - from package: kdelibs-bin

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

Error in other languages:
kded4: bevel nie gevind nie
kded4: comandă negăsită
kded4: comando não encontrado
kded4: commande introuvable
kded4: command not found
kded4: käsku ei ole
kded4: không tìm thấy lệnh
kded4: komanda nerasta
kded4: Kommando nicht gefunden.
kded4: kommandot finns inte
kded4: komut yok
kded4: nie znaleziono polecenia
kded4: níor aimsíodh an t-ordú
kded4: no se encontró la orden
kded4: no s'ha trobat l'ordre
kded4: opdracht niet gevonden
kded4: parancs nem található
kded4: perintah tidak ditemukan
kded4: príkaz nenájdený
kded4: příkaz nenalezen
kded4: команда не найдена
kded4: командата не е открита
kded4: 命令找不到
kded4: コマンドが見つかりません