Ok, I made some testing and found that the error is caused by the exe after applying the file loader to it, so that's why pesedit works (it apparently doesn't use fileloader). I used the original 1.16 exe and got to the game with all patches, but galaxypatch and PTE are both completely dependable on FileLoader, so by using the unaltered exe you're just playing the unpatched game. However, Fire Patch is a different story. I don't actually know why it uses the file loader altered exe, since it doesn't actually use fileloader, all things are made with cpk files and the edit save, like PESEDIT. Still, its altered exe also unlocks world challenge, so even tho I could load the game by using the unaltered exe, it couldn't load the edited data because it acted like I didn't have the dlc. This resulted in the cpk part of the patch being loaded, so kits, player faces, all of that, but the edited part not, so no updated transfers, wrong competition names and many dummy players, mainly in classic teams. So I thought, "I just need to find a cracked exe that unlocks the dlc", but the problem is that the ones I could find use the steam version of the game, which required some files that weren't present in the dvd version we're using. Ok, that was a problem, but I ended up finding a torrent of the steam version of the game with the world challenge dlc unlocked, so with that I just needed to install this version of the game, install the patch normally and then add the crack also present in the Torrent, replacing the exe that came with the patch and was effing everything, and voila, it actually worked! Apparently everything is working. I dont think I can link the torrent here, but if anyone wants to make the Fire Patch work and is getting the same error we did, I hope my experience can help.
The weirdest things still are why is the file loader version of the exe being installed by Fire Patch when it doesn't actually need it, why is this giving us errors when it works for some people (I searched and found that file loader was actually only updated to 1.12, but people made it work with the following versions by making some changes and adding the yair gameplay patch, and that's the exe that supposedly is being used by the Galaxy, Fire and PTE patches), and the weirdest one: It actually worked for me one random time, I was repeatedly trying to open the game with Fire Patch installed on the dvd version, and between the error, opening a white windo that stopped responding and not opening anything at all, it actually worked one time, but then it didn't anymore, so it's definitely something really weird happening that only someone with programming knowledge can look into. At least I now can play the Fire Patch with the method I described.