kdontchangethehostname: 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/kdontchangethehostname - from package: kdelibs3

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

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