carbon-sieve: 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/carbon-sieve - from package: carbonate

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

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