krb5-auth-dialog-preferences: 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/bin/krb5-auth-dialog-preferences - from package: krb5-auth-dialog

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

Error in other languages:
krb5-auth-dialog-preferences: bevel nie gevind nie
krb5-auth-dialog-preferences: comandă negăsită
krb5-auth-dialog-preferences: comando não encontrado
krb5-auth-dialog-preferences: commande introuvable
krb5-auth-dialog-preferences: command not found
krb5-auth-dialog-preferences: käsku ei ole
krb5-auth-dialog-preferences: không tìm thấy lệnh
krb5-auth-dialog-preferences: komanda nerasta
krb5-auth-dialog-preferences: Kommando nicht gefunden.
krb5-auth-dialog-preferences: kommandot finns inte
krb5-auth-dialog-preferences: komut yok
krb5-auth-dialog-preferences: nie znaleziono polecenia
krb5-auth-dialog-preferences: níor aimsíodh an t-ordú
krb5-auth-dialog-preferences: no se encontró la orden
krb5-auth-dialog-preferences: no s'ha trobat l'ordre
krb5-auth-dialog-preferences: opdracht niet gevonden
krb5-auth-dialog-preferences: parancs nem található
krb5-auth-dialog-preferences: perintah tidak ditemukan
krb5-auth-dialog-preferences: príkaz nenájdený
krb5-auth-dialog-preferences: příkaz nenalezen
krb5-auth-dialog-preferences: команда не найдена
krb5-auth-dialog-preferences: командата не е открита
krb5-auth-dialog-preferences: 命令找不到
krb5-auth-dialog-preferences: コマンドが見つかりません