connection unsucsessful

[boquetipo]

Hi there! I'm bran new on phonegap. I have made all the steps to make
the Hello World example. I run the project and I read "Hello World" on
the virtual device but around 20 seconds later, the app is closed...
(the virtual device is not).

Then I have tried writing an alert("1") on a <script> tag. I can read
it but another 20 s later a message is shown: "The connection to the
server was unsuccessful. (file:///android_asset/www/index.html").

I suposse that android_asset = /assets

Could anyone help me? Thank you.