vdb_render: 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/vdb_render - from package: libopenvdb-tools

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

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