bltk_get_system_release: 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/lib64/bltk/bin/bltk_get_system_release - from package: bltk

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

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