If you have problems with the tasks not solved by the documentation, please try to see if you have the same problems when running ajc directly on the command line.
When running Ant build scripts under Eclipse 2.x variants, you will get a VerifyError because the Eclipse Ant support fails to isolate the Ant runtime properly. To run in this context, set up iajc to fork (and use forkclasspath). Eclipse 3.0 will fork Ant processes to avoid problems like this.
Memory and forking: Users email most often about the ajc task running out of memory. This is not a problem with the task; some compiles take a lot of memory, often more than similar compiles using javac.
Forking is now supported in both the Ajc11CompilerAdapter (javac) and AjcTask (iajc), and you can set the maximum memory available. You can also not fork and increase the memory available to Ant (see the Ant documentation, searching for ANT_OPTS, the variable they use in their scripts to pass VM options, e.g., ANT_OPTS=-Xmx128m).
For questions, you can send email to firstname.lastname@example.org. (Do join the list to participate!) We also welcome any bug reports, patches, and features; you can submit them to the bug database at http://bugs.eclipse.org/bugs using the AspectJ product and Ant component.