kfmexec: command not found

Have You tried accessing the binary with the full path?

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/kfmexec - from package: kdelibs3

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