pxelinux-options: 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/pxelinux-options - from package: syslinux-perl

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

On Debian possible default full paths are:

/usr/bin/pxelinux-options - from package: syslinux-utils

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

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