pvfnoise: 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 CentOS possible default full paths are:

/usr/bin/pvfnoise - from package: mgetty-voice

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/pvfnoise - from package: mgetty-pvftools

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

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