There is still a file that can't be overwritten. Try the following hints from the installation instructions:

"There can be several reasons why a file in the Gamestudio folder is not accessible. Maybe WED or MED or another file was still running or still open, or a file or folder was set to system, read/only, or to restricted access. That file was not updated in that case. For updating you need to log in with administrative rights in a Window 2000, ME or XP system. Set the write protection property of your whole Gamestudio folder to 'Not Write Protected'. Make sure that all files are closed and accessible, and update again. You can repeat the update process as often as you want. If in doubt, the following method should help: set the read/only attribute of all files in the installation folder, and then set it back again for all files."