Technical issues with Heroes III.

What do you expect from a 20-byte file? It's practically empty; the game doesn't even show it in the list. Go through all your save files and find the latest one that has a normal size (around hundreds of kilobytes). You should continue the walkthrough from that save. Also, which Lord of the Rings map are you referring to (there are many), and what version is it? Please provide a link to the website where you downloaded it – the map file itself might be corrupted. I don't know what happened; the situation is unclear. It could be a problem with your version of Heroes, your hard drive, or Windows.