condor_update_machine_ad: 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/condor_update_machine_ad - from package: condor

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