I noticed that there was a few people myself included looking around the forum trying to find a solution to the Visual Studio No Source Available issues. Oddly enough I had one project that was working and one project that wasn't. After a bit of work trying to narrow it down I figured out something interesting.
In one project I was populating the form as modeless the other as modal. That being said I hd the issue whenever I used a modal form instead of a modeless. I am not sure if there is some other issue going on there but that is what I figured out thus far. I just thought I would make a post about it so that anyone else trying to find information on it might be able to get a solution here.
Now a quick note if your going to be using modeless forms your going to need to check out the issues with elockviolations and locking the document before accessing the database. There are other post on the form about this.
http://forums.autodesk.com/t5/NET/VB-Net-2013-eLockViolation/m-p/3901134/highlight/true#M34798