ksendemail: 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/ksendemail - from package: kdepim

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

On Debian possible default full paths are:

/usr/bin/ksendemail - from package: kontact

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

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