wavtopvf: 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/wavtopvf - from package: mgetty-voice

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

On Debian possible default full paths are:

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

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

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