krlogin: 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
/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/kerberos/bin/krlogin - from package: krb5-appl-clients

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