bltk_get_xdpyinfo: 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_xdpyinfo - from package: bltk

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

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