Could you post what version/build of K2 you are using?

 You could be facing one of two possible issues:

• Context-* isn't actually building
• Context-* is using a new GUID in its name and namespace that the rest of the project isn't aware of

I used to run into this problem almost constantly during a build. Typically what I had to do was show all of the extender projects, de-select the Context-* project for the build, build everything else, and then rebuild with it selected so that it would build successfully - this was due to an error regardingi something to do with metadata files. But sometimes it turned out that the GUID had changed and the rest of the project wasn't aware of it; in that case, I went through each file in the Context project and commented out the Context-* namespace declarations in everything.

I'm sure that this is a dirty hack and that the K2 team has a more elegant solution for this, but I hope my experiences give you at least a starting point towards a solution...

Hope this helps!

Lucas