ajc gone blind?

I'm currently working on some aspects that have to be written in annotation-style and am facing a quite bizarre problem:

ajc -g:vars -1.5 Main.java Point.java ObserverProtocol.java Binding.java
/path/to/project/src/ObserverProtocol.java:7 [error] Cannot read debug info for @Aspect to handle formal binding in pointcuts (please compile with 'javac -g' or '' in Ant)
abstract class ObserverProtocol {
^^^^^^^^^^^^^^^

1 error
make: *** [Main.class] Error 1

Any idea, what could be causing this?