So I think that we don't have a solution for this problem.
I have this problem too and I think that the data base schema is not really created.
So that we cannot load the example users and groups from ${jbpm.home}/install/src/demo/example.identities.sql
this file contains the list of users/password mentioned in the user guide.

the creation of DB schema by create.jbpm.schema give me an error :

[java] 10:53:42,560 FIN | [HibernateSessionResource] ----- beginning hibernate tx 6829563 ----------------------------------------

[java] 10:53:43,567 WRN | [JDBCExceptionReporter] SQL Error: -80, SQLState: 08000

[java] 10:53:43,567 SEV | [JDBCExceptionReporter] socket creation error

[java] ### EXCEPTION ###########################################

[java] 10:53:43,567 SEV | [HibernateSessionResource] hibernate transaction begin failed.  closing hibernate session

[java] org.hibernate.exception.JDBCConnectionException: Cannot open connection

[java]     at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:97)

[java]     at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)

[java]     at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:52)

[java]     at org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:449)

[java]     at org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:167)

[java]     at org.hibernate.jdbc.JDBCContext.connection(JDBCContext.java:142)

[java]     at org.hibernate.transaction.JDBCTransaction.begin(JDBCTransaction.java:85)

[java]     at org.hibernate.impl.SessionImpl.beginTransaction(SessionImpl.java:1353)

[java]     at org.jbpm.pvm.internal.tx.HibernateSessionResource.<init>(HibernateSessionResource.java:44)

[java]     at org.jbpm.pvm.internal.wire.descriptor.HibernateSessionDescriptor.construct(HibernateSessionDescriptor.java:87)

[java]     at org.jbpm.pvm.internal.wire.WireContext.construct(WireContext.java:487)

[java]     at org.jbpm.pvm.internal.wire.WireContext.create(WireContext.java:466)

[java]     at org.jbpm.pvm.internal.wire.WireContext.create(WireContext.java:455)

[java]     at org.jbpm.pvm.internal.wire.WireContext.get(WireContext.java:429)

[java]     at org.jbpm.pvm.internal.wire.WireContext.get(WireContext.java:339)

[java]     at org.jbpm.pvm.internal.wire.WireContext.get(WireContext.java:704)

[java]     at org.jbpm.pvm.internal.env.BasicEnvironment.get(BasicEnvironment.java:132)

[java]     at org.jbpm.pvm.internal.env.BasicEnvironment.get(BasicEnvironment.java:123)

[java]     at org.jbpm.db.Create$1.execute(Create.java:55)

[java]     at org.jbpm.db.Create$1.execute(Create.java:51)

[java]     at org.jbpm.pvm.internal.svc.DefaultCommandService.execute(DefaultCommandService.java:42)

[java]     at org.jbpm.pvm.internal.tx.StandardTransactionInterceptor.execute(StandardTransactionInterceptor.java:50)

[java]     at org.jbpm.pvm.internal.svc.EnvironmentInterceptor.executeInNewEnvironment(EnvironmentInterceptor.java:53)

[java]     at org.jbpm.pvm.internal.svc.EnvironmentInterceptor.execute(EnvironmentInterceptor.java:40)

[java]     at org.jbpm.pvm.internal.svc.RetryInterceptor.execute(RetryInterceptor.java:56)

[java]     at org.jbpm.pvm.internal.svc.SkipInterceptor.execute(SkipInterceptor.java:43)

[java]     at org.jbpm.pvm.internal.processengine.ProcessEngineImpl.execute(ProcessEngineImpl.java:300)

[java]     at org.jbpm.db.Create.main(Create.java:51)

[java] Caused by: java.sql.SQLException: socket creation error

[java]     at org.hsqldb.jdbc.Util.sqlException(Unknown Source)

[java]     at org.hsqldb.jdbc.jdbcConnection.<init>(Unknown Source)

[java]     at org.hsqldb.jdbcDriver.getConnection(Unknown Source)

[java]     at org.hsqldb.jdbcDriver.connect(Unknown Source)

[java]     at java.sql.DriverManager.getConnection(DriverManager.java:525)

[java]     at java.sql.DriverManager.getConnection(DriverManager.java:140)

[java]     at org.hibernate.connection.DriverManagerConnectionProvider.getConnection(DriverManagerConnectionProvider.java:133)

[java]     at org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:446)

[java]     ... 24 more

[java] ### EXCEPTION ###########################################

[java] ### EXCEPTION ###########################################

[java] 10:53:43,740 INF | [DefaultCommandService] exception while executing command org.jbpm.db.Create$1@18e261d

[java] org.hibernate.exception.JDBCConnectionException: Cannot open connection

[java]     at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:97)

[java]     at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)

[java]     at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:52)

[java]     at org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:449)

[java]     at org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:167)

...

could you help us please ??
and thanks in advance    

here the solution :
First, we ought start our database (hsql) with the command ant : ant start.hsqldb.server

and then we start our server application with : ant start.jboss or in preference with run.bat (in $jboss.home/bin) to see if we have some errors
because the ant command start jboss in the background.