kwatchgnupg: 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/kwatchgnupg - from package: kdepim

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

On Debian possible default full paths are:

/usr/bin/kwatchgnupg - from package: kleopatra

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

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