kleopatra: 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/kleopatra - from package: kdepim

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

On Debian possible default full paths are:

/usr/bin/kleopatra - from package: kleopatra

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

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