Current questions and answers regarding the map editor.

Is it possible to control the amount of experience given in chests? For example, so that a specific chest contains exactly 500 experience points and 1000 gold?

Yes, it is. In the map editor, select the chest, press the spacebar, select the "fixed" option, and enter

1

For example: if you enter "1", the chest will contain 1000 gold / 500 experience points.
2 - 1500/1000
3 - 2000/1500
and so on.

Added 14 minutes later

P.S. And one more problem - what's wrong with this script?

Trigger(REGION_ENTER_AND_STOP_TRIGGER, 'enti', 'RegionEnter');
function RegionEnter(Itil)
MessageBox(path.."ent.txt");
AddHeroCreatures(Itil, CREATURE ANCIENT TREANTS, 1);
Trigger(REGION_ENTER_AND_STOP_TRIGGER, 'enti', nil);
end;
end;

The first thing that catches the eye is CREATURE ANCIENT TREANTS and the missing quotes.
You need to specify the ID (number) of the monster from the game's documentation PDF file.
I understand that you need Ancient Ents. Then you need to write the following:

AddHeroCreatures("Itil", 54, 1);

and there might be one extra "end".