Hi John,
Yeah, you can email me fbkotler(pig's tail)myfairpoint(decimal point)net but it probably won't do you any good. I got as far as being able to write a bootloader and having it load a second stage and/or "kernal". Then I asked myself, "How is my OS going to be better than 'doze, 'nix, etc?". I realized I didn't know, and that was the end of my OS development. You're better off with the OSdev folks - there's a newsgroup too. Their advice is "read, read, read, and read some more" before you write a line of code. I see some folks saying, "I'm going to write an OS as soon as I figure out how to display a number." Be serious!
As far as the "-f rdf" problem goes, you're going to want a "minimal example" that displays the problem. Either start from scratch and add code until it breaks, as you suggest, or start with what you've got and subtract code until it "unbreaks". The latter might be easier(?). Post that up to bugzilla and you might get some action.
As I recall, rdoff was originally a kind of debugging aid to the original authors of Nasm, then someone figured out that you could make an executable out of it. I don't think it's ever been used much. I haven't even downloaded the latest version yet - that's how far away from "development" I've gotten...
Best,
Frank