bltk_wl_reader: 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/wl_reader/bin/bltk_wl_reader - from package: bltk

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

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