Q: I'm getting really weird errors when starting geoserver, like java.lang.VerifyError?

The number one cause of weird errors like this are classpath errors, many times with xerces. Most servlet containers make use of their own xml parsers. One solution to try is to remove xercesImpl.jar, xalan.jar, and xml-api.jar from geoserver.war (or geoserver/lib). If that doesn't work then try emailing [email protected] with your problem and a full stack trace.