Revit 2012: Error 1406: Could not write value Class to Key

 If you are getting this error:

  

    Could not write value Class to key\Software\Classes\CLSID

Please open the Regedit and go to:

Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID

Then review this post to change the permissions:

http://forums.autodesk.com/t5/Installation-Licensing/Error-1402-during-uninstallation-Could-not-open-key/td-p/2936782

NOTE:  Skip Step #1 because you are using CLISID key and you must execute Step #6 in order for the permissions settings to work properly.

Thanks to Martina Foss for confirming this solution and Avto Chachava for pointing me to the location of CLSID.