Now I am trying to export a feature based product. I created a feature
project including the HelloWorld plugin and the org.eclipse.rcp feature.
I've tried both with the .product file in HelloWorld and
HelloWorld.feature. In either case I get an exception.
Current DEV build does not support neither feature-based products nor
eclipse-application packaging type, so you need to wait for the next
build (tentatively, early next week) to try these features. I will also
try to update the tutorial to show use of eclipse-application packaging.
Unfortunately, this does not provide us with enough information to
diagnose the problem. Can you please re-run the build with debug log
enabled (-X parameter on cli) and either post build output here or
create new bugreport in JIRA  and attach the log there? Also, what
operating system you're using?