Update on the problem:
It seems that the game just crashes randomly (as in, I can never actually reproduce this myself, it just happens) when transfering to another map, getting an item, and in one instance when opening an item shop. Sometimes the crash does not happen for entire play-throughs of several hours. Sometimes it will happen several times in a row on one map. Completely random. When it crashes, it is not a script error that pops up, but the general windows error message saying something like game.exe encountered a problem and must close. However, I think it is related to the scripts, as I remember my older project of the same name never had this problem, nor do I have this problem with any other RPG VX games.
I have been struggling with this problem for some time now. It is particularly difficult to pinpoint because just removing one script at a time to find the problem script wont work due to the simple fact that the problem is so inconsistent that it would take hours and hours to thoroughly try one script to make sure it was not the one that causes the crash.
After spending even more time trying to fix this, it really seems like the problem lies somewhere in the data files.
To reproduce this error fairly reliably, I set up a test area filled with lots of events (treasure chests) and one auto-event that adds a party member and then disappears. Then I talk to an NPC which sends me into battle, and fairly reliably the game will crash upon exiting the battle and going back to the map (game.exe has encountered a problem and has shut down, or whatever). I tried doing pretty much the same thing in one of the game's actual maps, but the error did not seem to be as reliably replicated there.
I have started a brand new project, and brought the scripts over manually, all works fine. I bring the other data files over, game crashes.
I have started a new project, brought all of the map data, mapinfo data, and script data, and it works fine.
The problems start when I add in pretty much any of the other data files from the old project, though no 1 in particular seems to cause the problem. Any single one of them may cause the game to crash.
I have also done this in reverse, trying to replace existing data files one by one with ones from a new project, and same conclusion pretty much. The error stops when most of the data files are replaced, save for the ones mentioned above.
I have tested the scripts thoroughly as well, the best I could. There is another oddity here. I can remove the side view scripts and use just the default battle system, and the game doesn't crash any more, even with all of the datafiles the way they are. However, if I also made a new project and moved just the side view system files over and the game runs just fine without crashes until I bring the data files over.
I dug up an older version of the game back when it didnt have this problem and tested out that battle system (still side view, but older version) it worked fine on its own. I brought that battle system and replaced the newer one I was using in my project. Game crashes. I made a new project with the older tankentai sbs and threw in the old data files (sans the script datafile). Game crashes.
So it looks like the problem has something to do with my data files, but I have no idea what the problem could be still. As a last resort, and only if I absolutely have to, I will try a brand new project, only bringing over the maps and scripts, and rebuild the database from scratch (last resort because there are sooooooo many skills, items, pieces of gear, animations, and such that I made already) but I want to see what other people thought about this problem first, seeing as it is no guaranty that it will work anyways.
Any thoughts? What would you do in this situation?