Original code developed in VS2008 and the addin works fine and now I have upgraded the project to 2010 and made sure that it compiles to .net framework 3.5 as per the article:

http://files.solidworks.com/swexpress/API_Tips/SWX0051810_APItip.html the archive server needs the add-in to be in 3.5 or earlier.  But it still shows me the message box when I try to add this addin dll to "Debug Add-in":

The Archive Server could not open the Windows Registry

EPDM Client version: 11.02.0710

Any ideas what I may be missing?