tedster - 4:38 pm on Aug 5, 2010 (gmt 0)
I suggest you read this: Scraped or Stolen Content: What To Do First [webmasterworld.com]. It's a discussion from 2003, but the situation is not changed since then. You can find this reference and many more in the Hot Topics area [webmasterworld.com], which is always pinned to the top of this forum's index page. For this paritcular thread, look for the section called DEFENDING YOUR RANKINGS.
Accessing my site from China will show a 404 error. (To prevent copying, which clearly failed in this case. But at least they are not copying the new content uploaded recently.)
Do you guys think think is the reason why Google favors the scrapper site and treat mine as duplicate content?
Probably not - googlebot spiders your site from a US-based IP address.