kfile: 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/kfile - from package: kdelibs3

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

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