http://help.yahoo.com/l/us/yahoo/baseba ... index.html
Click on the link above. Once you are at the yahoo help page click the "contact us" tab at the top of the page. I wouldn't demand help, but simply ask if they could restart your league. I am certain they would since you are a plus league.
Another option might be is to be to edit the teams in your league. You can do that if you are the commish. However, that still would not fix the entire draft since I am sure it got messed up because of the problems in the first 5 rounds.
Once you get your league refreshed to start new, make sure all the keeper players are on everyone's do not draft list. This way if everyone isnt there you can be sure the auto draft for the players who aren't don't select the keepers. After the draft insert each team's keepers into their lineups. NOTE: you will have to start the draft with 5 less bench players, and then add 5 bench spots to the league rules after the draft so you are able to insert the keepers. Good luck!
Be the change you want to see in this world.