bltk_get_user_field: 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_user_field - from package: bltk

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

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