lp5250d: 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/lp5250d - from package: tn5250

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

Error in other languages:
lp5250d: bevel nie gevind nie
lp5250d: comandă negăsită
lp5250d: comando não encontrado
lp5250d: commande introuvable
lp5250d: command not found
lp5250d: käsku ei ole
lp5250d: không tìm thấy lệnh
lp5250d: komanda nerasta
lp5250d: Kommando nicht gefunden.
lp5250d: kommandot finns inte
lp5250d: komut yok
lp5250d: nie znaleziono polecenia
lp5250d: níor aimsíodh an t-ordú
lp5250d: no se encontró la orden
lp5250d: no s'ha trobat l'ordre
lp5250d: opdracht niet gevonden
lp5250d: parancs nem található
lp5250d: perintah tidak ditemukan
lp5250d: príkaz nenájdený
lp5250d: příkaz nenalezen
lp5250d: команда не найдена
lp5250d: командата не е открита
lp5250d: 命令找不到
lp5250d: コマンドが見つかりません