I dont quite understand the datafiles.cfg, what do I do there?
Because I think I put all the files in the right place, but now it just closes immediately
in main folder: DataFiles.cfg, Assimp32.dll, FO2238Config.exe, FOConfig.exe, FOnline.exe, FOnlineGL.exe
in "data" subfolder: faction001.zip, faction.zip, factioncritters.zip
in "data/cache" subfolder: default.cache
Try both FOnline.exe and FOnlineGL.exe.
If it doesn't work it's either something in newest client or you don't have FOnline.cfg/DataFiles2238.cfg
You can create them by running config apps.
Run FOConfig.exe and in "Net" tab setup server IP / port as 94.23.237.127 / 2238
Run FO2238Config.exe and in "Data Files" tab give paths to Fallout 2 Master.dat and Critter.dat.