Fifi666, can you confirm that changing your Windows username also changed the actual name of the folder which contains your settings within Documents and Settings?
My experience is that while what is displayed on the Start Menu, login screens, etc. will change when you change your Windows desktop's name will correctly update, the actual folder inside of Documents and Settings does not change because multiple programs have already stored the path of the old folder name in their settings which would break if the folder name changed.
If the folder name has not updated, you could try creating a new profile|user|desktop with non-special characters and that should create a user folder in Documents and Settings with that new name, which means that when that path is referenced by ICE, the string will be free of unicode characters.
Just trying to help you get to the bottom of this...