You can follow their directions at the bottom of the thread or you can do mine which I think is even easier. You will just need your serial number if you do it my way.
Go to the following folder on the main hard drive not your user folder: /Library/Preferences/
Hit either command-F or go to the File Menu and select Find. Select the word "Preferences" and then select "Kind" and choose "Other". This will bring up a whole bunch of parameters for which you can search. Find "File Visibility" and select it. I also click the Menu button so that I don't have to do that process every-time I'm looking for invisible files. Now hit OK
Now that File Visibility is your search parameter, select Invisible Items rather than Visible Items. You should see a file name ".SZIH6.5" Delete that file and start Now Contact. It will give you a the screen to enter your serial number. It should open fine and work just like normal.
Xplain's use of MacNews, AppleCentral and AppleExpo are not affiliated with Apple, Inc. MacTech is a registered trademark of Xplain Corporation. AppleCentral, MacNews, Xplain, "The journal of Apple technology", Apple Expo, Explain It, MacDev, MacDev-1, THINK Reference, NetProfessional, MacTech Central, MacTech Domains, MacForge, and the MacTutorMan are trademarks or service marks of Xplain Corp. Sprocket is a registered trademark of eSprocket Corp. Other trademarks and copyrights appearing in this printing or software remain the property of their respective holders.
All contents are Copyright 1984-2010 by Xplain Corporation. All rights reserved. Theme designed by Icreon.