makensis: 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 Debian possible default full paths are:

/usr/bin/makensis - from package: nsis

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

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