[RM3K] - PROJECT DID A ROLLBACK - BUT STILL GOT FILES - HELP

Ok, so this is the problem:
*I start up RPGMaker 2003.
*I open my project.
*RM3K loads an outdated version of the game, missing many maps.
*The maps, however, are still in my project folder.
*Opening the missing map files in .TXT shows the data (dialogues, events etc.) is all still in there.

The question is:
*How do I restore my project so it shows up all the maps again?

Little background on the project:
*This actually happened many years ago, and it's my first RPGMaker project ever. I think the rollback happened after a PC clean-up and putting my files back to my PC from a back-up. After that it just refused to show the game in its full state.

They are map files, but when I open them in .TXT they show the data.
Anyways, I just found out the only map's data that seems to be rollback'd in both RM3K and in the map file is the town map. The other maps just don't show up in RM3K project, but their data is still just fine in the map files.