I have a strong suspicion that you were assuming agreement where none existed. It's considered rude to make someone else lose face particularly in a social situation, and so often Chinese people will nod and appear to agree when in fact they are just saying that they've heard you.

American person: I think we should do X.
Chinese person: Yes, I agree.

Something that important in there is that the Chinese person *hasn't* agreed to the "we should do X" part. The Chinese person has merely agreed that the American person thinks that we should do X.

Doing business in China with Chinese is extremely difficult. Even if you are dealing with honest well-meaning people it will take a lot of time and effort, and as a foreigner you will no doubt run into people that are dishonest and non well-meaning.

One piece of advice that I have is don't talk business at a dinner. Talk about your family or about food, or ask about tourist attractions. Dinners are not about business.

Also, be prepared to play hard ball if necessary. In any Chinese contract discussion there will inevitably be some last minute problem in which they are trying to get some concession out of you. If you think that's whats going on, be prepared to pack up and fly home empty handed, and if it is negotiation tactic, then those problems will suddenly disappear.

One other point is that this is not so much an issue with Chinese culture than American culture. American culture is much less contextual and relationship oriented than most peoples in the world, and so the issues and misunderstandings Americans have in doing business in China, are similar to those that they have doing business in the Middle East or Latin America.