kdessh: 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/kdessh - from package: kdeutils

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

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