ck-xinit-session: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH

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/bin/ck-xinit-session - from package: xorg-x11-xinit

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