I downloaded the 4GK patch from SoccerAccess which installs its essencial files for FIFA 2002. But when it was ready to install a message sayin' "you can't write some files" or something like that appeared. What does this mean?
From what i could understand, since the patch installs files such as a new fifa2002.exe i'm not able to use another patch which also installs a new fifa2002.exe file (e.g.: the famous GK Patcher)???
Help me, please :(

you probably don't have the full installation of the game. Try to reinstall, click CUSTOM INSTALL and check all checkboxes. All patches should work now.