converttopdf: 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/converttopdf - from package: leptonica-progs

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

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