I guess you found your answer one year ago, but posting it as it appears as one of the first results when you google "JAXB can't handle interfaces".
It can occur when you try to marshall/unmarshall with Java classes containing members that are not declared static, and which (or one of their own members) don't have a non-arg constructor. For example a logger, or a JAXB Marshaller object that has a ValidationEventHandler with no non-arg constructor. Then JAXB tries to marshall/unmarshall them and fails with the above error message.
Just set them as 'static' and the problem should go.
If it doesn't resolve your problem, it can be more tricky with concerns about your web service document style. Take a look here: