probcons: 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/probcons - from package: probcons

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

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