Qt Creator's pop up gets frozen when click on Develop menu or Start Developing link

Hi. I'm an experienced programmer (core Java, C#, web/desktop applications) though I'm absolutely new to Linux and Qt and stuck right on the start. I installed Ubuntu 13.04 on my Toshiba laptop and then installed Qt Creator as it shown on http://developer.ubuntu.com/get-started/. In the IDE when I click on Develop menu or Start Developing link I get a frozen pop up window. And, there are no example projects. It looks my installation is broken. I did it twice, removed and installed again, no success. I appreciate if someone can give me a hint. Thank you

I don't see Qt Creator on the page you reference.

Exactly what did you install? What qt* packages are installed on your machine? Can you run "designer" from a command prompt?