lv2proc: 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/lv2proc - from package: lv2proc

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

Error in other languages:
lv2proc: bevel nie gevind nie
lv2proc: comandă negăsită
lv2proc: comando não encontrado
lv2proc: commande introuvable
lv2proc: command not found
lv2proc: käsku ei ole
lv2proc: không tìm thấy lệnh
lv2proc: komanda nerasta
lv2proc: Kommando nicht gefunden.
lv2proc: kommandot finns inte
lv2proc: komut yok
lv2proc: nie znaleziono polecenia
lv2proc: níor aimsíodh an t-ordú
lv2proc: no se encontró la orden
lv2proc: no s'ha trobat l'ordre
lv2proc: opdracht niet gevonden
lv2proc: parancs nem található
lv2proc: perintah tidak ditemukan
lv2proc: príkaz nenájdený
lv2proc: příkaz nenalezen
lv2proc: команда не найдена
lv2proc: командата не е открита
lv2proc: 命令找不到
lv2proc: コマンドが見つかりません