Hi @BarongBot,
The Home City file for Portuguese should be in C:\Users\[USERNAME]\Games\Age of Empires 3 DE\[0]\Savegame and the file should be called sp_Portuguese_homecity.xml. Re-installing the game does not alter these files.
If the xml file is there, delete it and re-launch the game. This will cause the game to create a new Portuguese Home City on startup.
I hope this helps you! Let me know if you cannot find the sp_Portuguese_homecity.xml.