Flash Builder: 1172 Definition Could not be found

I have an actionscript project in Flash Builder and get 1172开发者_JAVA百科 errors on these lines:

import flash.filesystem.File;
import flash.filesystem.FileMode;
import flash.filesystem.FileStream;

i'm comming from flash where i have to set in the publish settings that i want to compile an AIR application. I can't find an equivalent in flash builder.

In Flash Builder 4, I don't think you can create an ActionScript only AIR Project using the project setup wizard. You'll have to create an ActionScript project, and then manually add the AIR libraries to the classpath.