NiSimpleRead: 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/NiSimpleRead - from package: openni-examples

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

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