whups-reminders: 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 Debian possible default full paths are:

/usr/bin/whups-reminders - from package: php-horde-whups

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

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