STRANGE ERROR RM2003

Assertion failures (I'm guessing RM2k3 is written in VC++) accompanied with filenames like this typically pop up when trying to read from a file that doesn't exist or trying to read from a location that doesn't exist from within a file that does. The fact that you don't get it until you move up past a certain point makes it a little trickier to troubleshoot though.

I am drawing this from more general experience rather than any particular expertise in RM (because I have none) so take this with a grain of salt but based on what you're saying it sounds to me like something's wrong with the project definition files/database/whatever you use to refer to outside resource files, which is causing RM to include default resources that don't exist within your project, which in turn is causing RM to try to stream data from an empty .pas file at a location based on the player's coordinates and you are underflowing the file bounds by moving up past that point causing it to spit out an assertion failure as the file pointer moves to an invalid location and RM attempts to read from it

tl;dr try putting everything into a new project

In a way you kind of hope an error like this repeats/is predictable. Non-repeatable bugs that may or may not pop up again at a later date are really killer.

the GR_chipset.pas isn't a file in the rtp folder, it's a class inside the rpg_rt exe. The error was being caused by some kind of corrupted map file in the database. making a new, identical map fixed it because the new map wasn't corrupted.
I would wager the crash occured because rm2k(3) probably weren't designed with huge panorama maps in mind, and no other reason. but I would definitely suggest you make a backup of your project, just incase the error happens again, or more frequently, or causes a maptree error that's unrecoverable.