You probably just need to add files C and D to the list of Baggage files in your project. That's what Baggage is for. Ensuring content you need in your project gets copied to the server.
I tried to add those files, but no luck. The RoboHelp instructions about adding baggage files states I should be able to click "yes" to add the files, but I'm not getting that prompt (nor an error message).
Let's see here...
You are using X5... So you might be encountering the"Baggage Bug". Seems you have to manually edit one of the RoboHelp HTML project files for getting past that. I believe our wonderful Mr. Peter Grainge has something on his site about it. Lemme go see...
Ahhh yes, here it is.