All imports that aren't covered in the Processing reference have been removed since 2.0b7. It's in the revisions.txt, there have been multiple forum topics about this and some issues have been filed (for example File will be back in the next release). For now you can add these lines to your sketch to fix this:

1. import java.io.File;
2. import java.util.Iterator;

It is becoming a FAQ...
So, general advices I gave lot of times:
- When you upgrade, read the list of changes!
- Search the forum when you have a problem. Although here, you should search 2.0b7, not 2.07 which doesn't exists.
Side note: these are classes, not functions.

Sorry, I forgot about the revisions.txt document.

@ amnon.owed: That's great thanks for that tip, it fixed things here.