Faore, did you replaced a long tileset for a shorter one? If yes, I guess that you have selected a tile in a position that the new tileset doen't have, like the tile in row 48, column 3 when the new tileset only has 30 rows. Just a hint.
I've had an error similar to this, which was caused by a specific event. It was a modified PC, which was supposed to have the screen light up when you use it. However, when I copied it into a new map, since there were different tilesets, the graphics became (none).
Check all your events, and make sure there isn't anything wrong. Although, it's easier to delete your events one by one until the map works.
try copy pasting an already made door event and only edit the warp location near the end of the event. if it works you can change the graphic of event too(the problem could be because not all door tiles are the same) and change again