pdftops: 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/pdftops - from package: poppler-utils

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

On Debian possible default full paths are:

/usr/bin/pdftops - from package: poppler-utils

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

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