Eclipse won't start a new Android project anymore

A few weeks ago, I followed a tutorial to get Eclipse and the Android开发者_Go百科 Development Kit up and running. I successfully built the test application and ran it on a virtual device.

Tonight I finally went back to do the next step in the tutorial, but when I went to start a new project there wasn't an option to start a new Android project. Even searching for it didn't produce anything. Window -> Preferences doesn't have an Android preferences dialog, either. The developer tools are still installed, though, according to Help -> Install New Software.

I'm using Eclipse Galileo 3.5.2 on Ubuntu 10.10 Maverick Meerkat. I just recently upgraded. I remember I had to install some additional packages to get Eclipse to run the Android stuff last time. I haven't uninstalled those, so I don't know what's causing the problem.

What's causing this problem, and what can I do to fix it?

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Re-check following things..........

1.) ADT is installed.

2.) Android SDK path is provided or not.