pv_export: 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/pv_export - from package: csound-utils

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

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