This is a problem after update OpenOffice from fedora.com server. It has something with the jpackage's Java. So I worked it around by removing the OpenOffice of Fedora core 4, installing openoffice2.0 beta form the offical site: openoffice.org.
and more:if you still can't start up very fast,try to set your default printer into the virtual pdf printer so that it won't connect to the default printer on startup.