Sample-NiUserSelection: 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 Debian possible default full paths are:

/usr/bin/Sample-NiUserSelection - from package: openni-utils

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

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