lpr.cups: 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
/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/lpr.cups - from package: cups

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