[HELP!!!] I need to localize the game into Russian.

You should have purchased it on the Booki website – the official локализатор for Heroes 5. But anyway... Step 1: You need someone to share the Russian language files with you, including the text files, data.pak, and everything else that might be useful. Maybe here is what you need. But I can't promise – the file is too small; I would expect a file larger than 5 MB, but it's only 1.5 MB. You can download a Russian version from torrents to avoid the hassle (you bought it officially, legally, and you have a key for the game on Ubi.com. You can enter it even in a pirated version). Step 2. Now, somehow you have the Russian version. Download the patch from here. There are two versions – Booki's and the regular one. If you don't download anything from torrents, you need the regular version. For simplicity, here's a link.