unprotoize: 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/unprotoize - from package: gcc

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

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