cpack3: 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/cpack3 - from package: cmake3

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

Error in other languages:
cpack3: bevel nie gevind nie
cpack3: comandă negăsită
cpack3: comando não encontrado
cpack3: commande introuvable
cpack3: command not found
cpack3: käsku ei ole
cpack3: không tìm thấy lệnh
cpack3: komanda nerasta
cpack3: Kommando nicht gefunden.
cpack3: kommandot finns inte
cpack3: komut yok
cpack3: nie znaleziono polecenia
cpack3: níor aimsíodh an t-ordú
cpack3: no se encontró la orden
cpack3: no s'ha trobat l'ordre
cpack3: opdracht niet gevonden
cpack3: parancs nem található
cpack3: perintah tidak ditemukan
cpack3: príkaz nenájdený
cpack3: příkaz nenalezen
cpack3: команда не найдена
cpack3: командата не е открита
cpack3: 命令找不到
cpack3: コマンドが見つかりません