I suspect your problem is a cable that has slipped off the top end of the centerboard. If you have an opportunity to careen your boat on a sandy shore or grassy area, do so, by pulling the mast top down with the halyard off to one side, then tieing the mast down to a tree or vehicle. This is easily done by one person. Release the cb sheets, and go around to the hull side of the boat and deploy the cb by hand. If you notice that it scratches/scrapes as it comes out, a cable off to one side is the culprit. (the other thing it might be is pebbles or sand, but I doubt it, as that usually washes out when deployed.) Go around to the cockpit side, remove the pivot bolt, and centerboard and check to see if indeed it is not riding along the top of the cb. You can put it back in place, then reinsert the cb, but this is a two person job.
The book and CD are still available, (in fact I have lots in stock). See the sticky at the top of this forum:
http://forum.daysailer.org/forum/viewtopic.php?t=1346
or e-mail me at roger02 att mts dott net for ordering details.