last-pair-probs: 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/last-pair-probs - from package: last-align

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

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