Daishaclaire: Unfortunately, I don't know what you need to do. However, I can explain how you might hunt for where the XP cap is stored.
1. Try using a tool like grep to search for the string "161000" in the game's files. (Since you're using Linux, grep should already be installed.)
I found 161000 in DEFAULT.BIF, and changed it to -1, which promptly broke the whole game. Crashed out before even displaying the beamdog splash screen.
2. If that fails, the data may be packed into some archive. Since BG:EE is a well known game with mods, there should be a tool out there that can decompress the files. Then grep for
I was hoping to get out of this, as I spent a couple of hours trying to compile WeiDU this morning without success, but since modifying the .BIF by hand led to catastrophic failure, I guess it's back to the Perl mines.
3. If that fails, you can try to search for the cap in binary files; you will need to convert it to hexadecimal.
4. If that fails, it's time to bring out a debugger and maybe patch the executable file. This is a lot more involved than the previous steps, and is an advanced technique. (I believe this sort of thing had to be done for TuTu in order to change the starting XP that new characters get, for example.)
I don't think this would be fruitful. Since I found the 161000 string in the .BIF, I doubt it's directly referenced in the executable binary.
Also, why is your game in /usr/local/share/games rather than somewhere in your home directory? (The Linux games from GOG I've installed default to "~/GOG Games" as their installation location.) Are you sure you are pitting the .2DA file in the correct installation's override directory?
I used the ./play.it scripts to repackage the GOG installer, which I and many other linux users have found installs a broken game. It repackages GOG-provided installer rolling in a couple of dependencies that GOG gets wrong. It's basically a work-around for a chronic problem with GOG games whose devs refuse to make 64 bit software. The ./play.it scripts repackage the GOG scripts to install to usr/local/share/games instead of the home directory. It's kind of a pain in the butt because you have to sudo to tinker with it at all, but it's handily available for all users to play, instead of locked away in one home directory. Not that anyone else uses my machine.
Thanks for your advice, I'll go back to trying to get WeiDU working.