Do you mean round darker spots ON FILM or on PRINT? I ask because it sounds like you may be talking about lens flare but that will appaer as brighter spots on print and darker spots on film.
Another creative possibility is, you may have a very strange light leak which casts a shadow on film.
Can you possibly post an image of film or print, so we can see what you are talking about? I had a Rolleicord V for about a year but did not experience such problems. I doubt very much you have a lens flare either....
It's clear my explanation was a bit confusing... Spots are on film and appear as brighter spots on film and darker spots on print. Today evening I'll post a scan from a contact sheet to clarify it.