convertfilestops: 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/convertfilestops - from package: leptonica-progs

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

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