At the first step of installation procedure the next page had to be filled in: Name, login name, password, name of computer.

The login name was filed which included unacceptable characters (in my case, a space character). I approved the error by not entering a space character; instead, I entered an underline symbol (again considered an unacceptable symbol). At the first error occurrence, I received a warning note in the language I was installing Karmic Koala (Dutch or else Nederland’s). After the second error event I got the warning note in English (a pop-up message window, with an ok button). Clicking this button did not get me out of this window. Even when I tried the left top icon I could not shut this window. The only means I could get out of it was pushing the hardware switch button on my PC.