Speed/Display issues/unfamiliar error messages, crashes/hangs or any other problems regarding ARCHICAD (Example: I get an error message when the 3D Window is generated, please help!).
Note: If your problem seems to be an ARCHICAD error please always report it to your local reseller!
Have you tried changing locale settings, as suggested above?
Worked for me.
I don't know how I haven't saw that solution with locale settings - I have noticed this solution only after posting my post. I confirm that changing locale settings fixed all my issues. It was a headache for me for more than a week...