We have been seeing this issue in DWR/Spring integrations. It looks like the Spring guys changed (changed since Spring 3.x?) their schema and now require an id attribute on top-level annotation-config elements. DWR uses a Spring class to parse the XML and it throws the following error:

“Configuration problem: Id is required for element ‘annotation-config’ when used as a top-level tag”

It appears for now adding an id attribute resolves the issue. I will continue to look into this.