No, the persistence issue is not causing the Connection refused error. It sounds like two separate problems to me.
What does your persistence.xml look like? Currrently, AS7 works with Hibernate 4 as the persistence provider. We added a way to work with Hibernate 3 as well recently. I googled for information on IBatis but didn't get clear answers. Is it a JPA 2.0 persistence provider? We are also working on the ability to plug in other persistence providers (that effort is continuing on a git branch).
Scott