我正在使用 Grails 2.3、sts3.3、activiti5.12.1，并按照以下链接中的步骤操作：https ://code.google.com/p/grails-activiti-plugin/wiki/VacationRequestSampleApplication
一切正常grails run-app，直到出现以下异常：
| Loading Grails 2.3.0
| Configuring classpath.
| Environment set to development.....
| Packaging Grails application.....
| Compiling 1 source files.....
| Running Grails application
| Server running. Browse to http://localhost:8080/HC_WFFA_WEB
Configuring Activiti Process Engine ...
... finished configuring Activiti Process Engine.
Configuring Activiti Process Engine with Spring Security ...
... finished configuring Activiti Process Engine with Spring Security.
Configuring Spring Security Core ...
... finished configuring Spring Security Core
Error initializing the application: null
java.lang.NullPointerException
at org.codehaus.groovy.grails.plugins.services.ServiceBeanAliasPostProcessor.postProcessBeanFactory(ServiceBeanAliasPostProcessor.groovy:54)
at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:694)
at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:684)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:461)
at org.codehaus.groovy.grails.commons.spring.DefaultRuntimeSpringConfiguration.getApplicationContext(DefaultRuntimeSpringConfiguration.java:153)
at org.codehaus.groovy.grails.commons.spring.GrailsRuntimeConfigurator.configure(GrailsRuntimeConfigurator.java:169)
at org.codehaus.groovy.grails.commons.spring.GrailsRuntimeConfigurator.configure(GrailsRuntimeConfigurator.java:127)
at org.codehaus.groovy.grails.web.context.GrailsConfigUtils.configureWebApplicationContext(GrailsConfigUtils.java:122)
at org.codehaus.groovy.grails.web.context.GrailsContextLoader.initWebApplicationContext(GrailsContextLoader.java:108)
at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:112)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4939)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5434)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1559)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1549)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
at java.util.concurrent.FutureTask.run(FutureTask.java:166)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:724)
| Error Forked Grails VM exited with error