a5booklet: 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/a5booklet - from package: dvidvi

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

Error in other languages:
a5booklet: bevel nie gevind nie
a5booklet: comandă negăsită
a5booklet: comando não encontrado
a5booklet: commande introuvable
a5booklet: command not found
a5booklet: käsku ei ole
a5booklet: không tìm thấy lệnh
a5booklet: komanda nerasta
a5booklet: Kommando nicht gefunden.
a5booklet: kommandot finns inte
a5booklet: komut yok
a5booklet: nie znaleziono polecenia
a5booklet: níor aimsíodh an t-ordú
a5booklet: no se encontró la orden
a5booklet: no s'ha trobat l'ordre
a5booklet: opdracht niet gevonden
a5booklet: parancs nem található
a5booklet: perintah tidak ditemukan
a5booklet: príkaz nenájdený
a5booklet: příkaz nenalezen
a5booklet: команда не найдена
a5booklet: командата не е открита
a5booklet: 命令找不到
a5booklet: コマンドが見つかりません