kdedoc: 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/kdedoc - from package: kdesdk

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

On Debian possible default full paths are:

/usr/bin/kdedoc - from package: kdesdk-scripts

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

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