Oh, just realized the new server is running 1.5 and then saw this note.
We are still working against Java 1.4, and will continue to always support it. But many users are upgrading to 1.5, as it can lead to some nice speed increases. GeoServer 1.2 currently will not work by default with Java 1.5, due to a library that was present in 1.4, but is not standard in 1.5. We do not want to distribute it with GeoServer since it adds an extra 1.5 megabytes, and most users have it by default. If you are using GeoServer with Java 1.5 and are getting errors (like a TransformerFactoryConfiguration error, or simply a 500 internal Server error) then we recommend downloading the latest xalan.jar from xerces. You can add this just to GeoServer, by placing it in the GeoServer WEB-INF/lib/ directory. Or you can permanently add it to your Java installation, so that you won’t have to copy it over during GeoServer upgrades, by putting it in JAVA_HOME/jre/lib/ext.
sorry for not checking on that first.
-dylan