makecert: 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/makecert - from package: mono-devel

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

On Debian possible default full paths are:

/usr/bin/makecert - from package: mono-devel

You may install the required package with command apt-get install {package}

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