guilt-next: 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/guilt-next - from package: guilt

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

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