zinnia_convert: 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/zinnia_convert - from package: zinnia-utils

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

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