convertfilestopdf: 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/convertfilestopdf - from package: leptonica-progs

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

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