To improve security, we will soon start forcing password resets for any account that uses a weak password on the next login. If you have a weak password or a defunct email, please update it now to prevent future disruption.
When I couldn't extract an archive, it was because I used an outdated version of 7z/Winrar, because something went wrong while downloading the game and the archive was corrupted (you may ask for the md5sum of the file in the game thread) or because of a hard disk issue.
What's the error message?