for the first 2 and maybe for all go to this linkhttp://www.gnutellaforums.com/showthread.php?s=&threadid=27104&highlight=awaitin g+sources

waiting in line means that you are waiting for other users which tried getting the download before, to finish the download from the host as he doesn't allow more than a certain number of people

waiting for busy hosts means that it's waiting for a position.

and when you refresh it clears those because, it tries to connect again