Thank you all.
I've solved this problem following Barry's advice: After I installed 2 features under "Database Development", it's OK now.
@Ramesh, I've tried a lot before I sent this mail. For example I uninstalled the Teiid Designer plugins and reinstalled them. But that didn't work. I'm in Mac OS X 10.9.1, using the latest version of Eclipse Kepler. Is this a bug in Teiid Designer?
@Mark, I've followed the instructions in that page =).
I tried to post in forum using safari, everything is OK. But it's not so lucky in Chrome(v32.0.1700.107 in OS X 10.9.1). Just as I said, it's hard for me to leave a page for another page.
Again, I appreciate your support. It's so nice of you.