I haven't done anything with my DNN site for a while.  Today I open the solution in VS2005, and I am greeted with 103 errors and 9 warnings about how a bunch of names aren't declared and "Namespace or type specified in the Imports 'DotNetNuke.Services.Log.EventLog' doesn't contain any public member or cannot be found.' (this warning appeared for other DotNetNuke namespaces too, and Microsoft.ApplicationBlocks.Data).  All the Dlls are still in the bin folder.  If I go to the References area on the property pages for the project, the only references showing are Microsoft.VisualBasic and all the System.*.  If I click the Add Reference button, browse to DotNetNuke.dll in the bin folder and add it, it looks like it's adding it (I get the hourglass for a while), but it isn't added to the list.  What's going on here?  How do I fix it?