workrave: 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/workrave - from package: workrave

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

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