Re: Rolls, Dizziness and Nausea
Sympathies on your problem. I helped teach an older student with the same difficulty, and it took a frustratingly long time for rolls to get easier for her.
You might try practicing being dizzy in some safer circumstance, like sitting on the merry-go-round at the park, or just spinning in circles. The problem is not really the inner ear, it's the brain saying "Yikes! This is wrong!" and eventually it may learn to cope.
One of the AikiWeb blogs had entries from a student who got horribly nauseated when rolling; he found that Dramamine did help.
Does rolling onto your back and up to sitting ("koho tento undo") bother you? If it bothers you just a tiny amount, it would make a good experimental lab for finding out what approaches will help, since it's much safer than forward or backward rolls. You can try controlling your breathing, as many posters have suggested, and also controlling your eye direction--try to keep looking forward as you roll back.
Best of luck. Rolling is great once you get it, so you have something to look forward to.