djvusmooth: 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/djvusmooth - from package: djvusmooth

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

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