sms_ntsc_demo: 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

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/sms_ntsc_demo - from package: sms_ntsc-demos

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