I was naive, I didn't know translated WordPress - WordPress CN http://cn.wordpress.org/ isn't compatible with original WordPress (EN).
Thus, I would like to reinstall my site to WordPress EN but how can I do so? How can I keep my WordPress posts and database?
I installed WordPress English and uploaded Chinese translation files for my Chinese site. Later, I had upgraded to WordPress CN as I discovered that it would save me some troubles as I didn't need to reupload translation files whenever WordPress upgrades were available. Since then, many problems arose, such as: fatal errors, plugins conflict, could't launch bbPress, etc.
Contacted WordPress CN but no one has answered me. :(
WordPress master, please help me!!!