AddressBook example gives exception!!!

Hi,

I was trying to understand and run the AddressBook Application from the SVN source. Initially I got some compilation issues. later on I was succesfully able to run/debug it.
However, I am getting the following exception in DatabaseHelper class (at the line cityContainer.commit();):

com.mysql.jdbc.exceptions.MySQLIntegrityConstraintViolationException: Column 'id' cannot be null
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:931)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2985)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1631)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1723)
at com.mysql.jdbc.Connection.execSQL(Connection.java:3283)
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1332)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1604)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1519)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1504)
at com.vaadin.data.util.sqlcontainer.query.TableQuery.executeUpdateReturnKeys(TableQuery.java:474)
at com.vaadin.data.util.sqlcontainer.query.TableQuery.storeRow(TableQuery.java:200)
at com.vaadin.data.util.sqlcontainer.SQLContainer.commit(SQLContainer.java:914)
at com.vaadin.addon.sqlcontainer.demo.addressbook.data.DatabaseHelper.fillContainers(DatabaseHelper.java:131)
at com.vaadin.addon.sqlcontainer.demo.addressbook.data.DatabaseHelper.<init>(DatabaseHelper.java:49)
at com.vaadin.addon.sqlcontainer.demo.addressbook.AddressBookApplication.<init>(AddressBookApplication.java:62)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at java.lang.Class.newInstance0(Unknown Source)
at java.lang.Class.newInstance(Unknown Source)
at com.vaadin.terminal.gwt.server.ApplicationServlet.getNewApplication(ApplicationServlet.java:82)
at com.vaadin.terminal.gwt.server.AbstractApplicationServlet.createApplication(AbstractApplicationServlet.java:978)
at com.vaadin.terminal.gwt.server.AbstractApplicationServlet.findApplicationInstance(AbstractApplicationServlet.java:801)
at com.vaadin.terminal.gwt.server.AbstractApplicationServlet.service(AbstractApplicationServlet.java:456)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:602)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
at java.lang.Thread.run(Unknown Source)

Please suggest.

Thanks,
Vikash