Are you using the beta version of
Java SDK 1.4? I had some trouble with some of my import statements when I switched from 1.3. I think the problem is that it doesn't make sense to import a class into another class when they are both in the same default package. The updated compiler recognizes this error, because it expects that every import statement will include a '.'. For example:
import java.io.*; // This is ok
import aClassInSamePackage; // This is NOT ok
I wrote a perl script to fix this problem in the code I'm maintaining, since there are over 60 .java files in the program. It pulls out the bad import statements. If you would like the script, email me and I'll send it to you.