conv_lib.mpb: 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"

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