pages2epub: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH

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/pages2epub - from package: pages2epub

You may install the required package with command apt-get install {package}
Error in other languages:
pages2epub: bevel nie gevind nie
pages2epub: comandă negăsită
pages2epub: comando não encontrado
pages2epub: commande introuvable
pages2epub: command not found
pages2epub: käsku ei ole
pages2epub: không tìm thấy lệnh
pages2epub: komanda nerasta
pages2epub: Kommando nicht gefunden.
pages2epub: kommandot finns inte
pages2epub: komut yok
pages2epub: nie znaleziono polecenia
pages2epub: níor aimsíodh an t-ordú
pages2epub: no se encontró la orden
pages2epub: no s'ha trobat l'ordre
pages2epub: opdracht niet gevonden
pages2epub: parancs nem található
pages2epub: perintah tidak ditemukan
pages2epub: príkaz nenájdený
pages2epub: příkaz nenalezen
pages2epub: команда не найдена
pages2epub: командата не е открита
pages2epub: 命令找不到
pages2epub: コマンドが見つかりません