I deploy jbpm 4.2 in postgresql. All jbpm tables are created in postgresql database. But when calling Configuration.getProcessEngine(), I got the following error: org.postgresql.util.PSQLException: ERROR: syntax error at or near "$1"

The StackTrace is the following:

INFO: building session factory
Mar 31, 2010 10:45:20 AM org.hibernate.impl.SessionFactoryObjectFactory addInstance
INFO: Not binding factory to JNDI, no JNDI name configured
Mar 31, 2010 10:45:20 AM org.hibernate.util.JDBCExceptionReporter logExceptions
WARNING: SQL Error: 0, SQLState: 42601
Mar 31, 2010 10:45:20 AM org.hibernate.util.JDBCExceptionReporter logExceptions
SEVERE: ERROR: syntax error at or near "$1"
Mar 31, 2010 10:45:20 AM org.hibernate.util.JDBCExceptionReporter logExceptions
WARNING: SQL Error: 0, SQLState: 42601
Mar 31, 2010 10:45:20 AM org.hibernate.util.JDBCExceptionReporter logExceptions
SEVERE: ERROR: syntax error at or near "$1"
Mar 31, 2010 10:45:20 AM org.jbpm.internal.log.Jdk14Log info
INFO: exception while executing command org.jbpm.pvm.internal.cmd.CheckDbCmd@dc67248
org.jbpm.api.JbpmException: no jBPM DB schema: no JBPM4_EXECUTION table.   Run the create.jbpm.schema target first in the install tool.
    at org.jbpm.pvm.internal.cmd.CheckDbCmd.execute(CheckDbCmd.java:50)
    at org.jbpm.pvm.internal.svc.DefaultCommandService.execute(DefaultCommandService.java:42)
    at org.jbpm.pvm.internal.tx.StandardTransactionInterceptor.execute(StandardTransactionInterceptor.java:54)
    at org.jbpm.pvm.internal.svc.EnvironmentInterceptor.executeInNewEnvironment(EnvironmentInterceptor.java:53)
    at org.jbpm.pvm.internal.svc.EnvironmentInterceptor.execute(EnvironmentInterceptor.java:40)
    at org.jbpm.pvm.internal.svc.RetryInterceptor.execute(RetryInterceptor.java:55)
    at org.jbpm.pvm.internal.svc.SkipInterceptor.execute(SkipInterceptor.java:43)
    at org.jbpm.pvm.internal.cfg.ProcessEngineImpl.checkDb(ProcessEngineImpl.java:177)
    at org.jbpm.pvm.internal.cfg.ProcessEngineImpl.buildProcessEngine(ProcessEngineImpl.java:170)
    at org.jbpm.api.Configuration.getProcessEngine(Configuration.java:161)
   
Exception in thread "main" org.jbpm.api.JbpmException: no jBPM DB schema: no JBPM4_EXECUTION table.   Run the create.jbpm.schema target first in the install tool.
    at org.jbpm.pvm.internal.cmd.CheckDbCmd.execute(CheckDbCmd.java:50)
    at org.jbpm.pvm.internal.svc.DefaultCommandService.execute(DefaultCommandService.java:42)
    at org.jbpm.pvm.internal.tx.StandardTransactionInterceptor.execute(StandardTransactionInterceptor.java:54)
    at org.jbpm.pvm.internal.svc.EnvironmentInterceptor.executeInNewEnvironment(EnvironmentInterceptor.java:53)
    at org.jbpm.pvm.internal.svc.EnvironmentInterceptor.execute(EnvironmentInterceptor.java:40)
    at org.jbpm.pvm.internal.svc.RetryInterceptor.execute(RetryInterceptor.java:55)
    at org.jbpm.pvm.internal.svc.SkipInterceptor.execute(SkipInterceptor.java:43)
    at org.jbpm.pvm.internal.cfg.ProcessEngineImpl.checkDb(ProcessEngineImpl.java:177)
    at org.jbpm.pvm.internal.cfg.ProcessEngineImpl.buildProcessEngine(ProcessEngineImpl.java:170)
    at org.jbpm.api.Configuration.getProcessEngine(Configuration.java:161)

Any help would be greatly appreciated.

Thanks,

Feng