upmpost: 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/upmpost - from package: texlive-binaries

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

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