The issue is that the JAR files are located in different places in 5.1., thus I doubt that Dev Studio knows of the new locations out of the box, which means it will be difficult to create a server. There is a workaround for this. Look at plugins\org.eclipse.jst.server.generic.jboss_1.6.1.v200904151730\servers\ , at the various *.serverdef files. Make a copy of one of the files as jboss5.serverdef and change the setting in it to reference the new locations. You could even try using a copy of the file form the latest JBoss Tools download. By the way, I used Eclipse 3.5 + JBoss Tools 3.1 to locate the above directory - in Dev Studio it might be at a different location - search for *.serverdef files. View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4244141#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...