Ordinarily, the annual conference of theater owners known as CinemaCon is not the setting for much controversy. That's not the case this year. Regal Entertainment and AMC Entertainment, the nation's top two exhibitors, have reportedly made it known that they don't like the terms that Disney is seeking for sharing revenue with the exhibitors. Indeed, the two chains said on Wednesday that they have halted advance sales of tickets for Iron Man 3, scheduled to open on May 3. Some analysts expect it to open with more than $150 million in domestic sales. We hope to reach agreement and get tickets on sale as soon as possible so it doesn't affect opening weekend, Ryan Noonan, an AMC spokesman, said Wednesday in a statement. In an interview with the Wall Street Journal, AMC chief Gerry Lopez said that Disney is demanding a bigger cut of the revenue for Iron Man 3 than for anything I have seen in my time in the industry. ... It's enough for us to pause and push back. Neither Disney nor any of the other theater chains is commenting on the dispute, but the Journal said that Cinemark USA, the nation's third-largest exhibitor, is also refusing to sell tickets, but that Carmike Cinemas, the fourth-largest, reached a new deal with Disney on Thursday and began selling them.