Hi dude It means that derby driver is not in your application server classpath. so you should add derbyClient.jar in your application server common or shared library. for example it could be glassfish_home\domain1\lib or tomcat_home\shared\lib what ever place your shared library is.
Further, it was said to be "Caused by: org.apache.derby.client.am.DisconnectException: java.security.PrivilegedActionException : Error opening socket to server localhost on port 1527 with message : null"
Could you please help with this? I have no idea what the problem is.