toppler: 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 CentOS possible default full paths are:

/usr/bin/toppler - from package: toppler

You may install the required package with command yum install {package}

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