guilt-guard: 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/bin/guilt-guard - from package: guilt

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