Middlegen Mapping Exception

Hi!

Can anyone help me? I'm a newbie of Middlegen.

I have an error when I tried to launch <ant hbm2java>

<target name="hbm2java" description="Generate .java from .hbm files.">
<taskdef
name="hbm2java"
classname="net.sf.hibernate.tool.hbm2java.Hbm2Java Task"
classpathref="lib.class.path"
/>

<hbm2java output="${build.gen-src.dir}">
<fileset dir="${build.gen-src.dir}">
<include name="**/*.hbm.xml"/>
</fileset>
</hbm2java>
</target>

I used Middlegen Hibernate plugin, I added hibernate-extensions-2.1.3
so that Hbm2JavaTask can be recognized. Besides, I imported all
neccessary hibernate jar by the classpath (lib.class.path).

java.lang.NoClassDefFoundError: net/sf/hibernate/MappingException
ava.lang.NoClassDefFoundError: net/sf/hibernate/MappingException
at
net.sf.hibernate.tool.hbm2java.Hbm2JavaTask.proces sFile(Hbm2JavaTask.java:145)
at
net.sf.hibernate.tool.hbm2java.Hbm2JavaTask.execut e(Hbm2JavaTask.java:93)
at
org.apache.tools.ant.UnknownElement.execute(Unknow nElement.java:275)
at org.apache.tools.ant.Task.perform(Task.java:364)
at org.apache.tools.ant.Target.execute(Target.java:34 1)
at org.apache.tools.ant.Target.performTasks(Target.ja va:369)
at
org.apache.tools.ant.Project.executeSortedTargets( Project.java:1216)
at org.apache.tools.ant.Project.executeTarget(Project .java:1185)
at
org.apache.tools.ant.helper.DefaultExecutor.execut eTargets(DefaultExecutor.java:40)
at
org.eclipse.ant.internal.ui.antsupport.EclipseDefa ultExecutor.executeTargets(EclipseDefaultExecutor. java:32)
at org.apache.tools.ant.Project.executeTargets(Projec t.java:1068)
at
org.eclipse.ant.internal.ui.antsupport.InternalAnt Runner.run(InternalAntRunner.java:423)
at
org.eclipse.ant.internal.ui.antsupport.InternalAnt Runner.main(InternalAntRunner.java:137)

at
net.sf.hibernate.tool.hbm2java.Hbm2JavaTask.proces sFile(Hbm2JavaTask.java:149)
at
net.sf.hibernate.tool.hbm2java.Hbm2JavaTask.execut e(Hbm2JavaTask.java:93)
at
org.apache.tools.ant.UnknownElement.execute(Unknow nElement.java:275)
at org.apache.tools.ant.Task.perform(Task.java:364)
at org.apache.tools.ant.Target.execute(Target.java:34 1)
at org.apache.tools.ant.Target.performTasks(Target.ja va:369)
at
org.apache.tools.ant.Project.executeSortedTargets( Project.java:1216)
at org.apache.tools.ant.Project.executeTarget(Project .java:1185)
at
org.apache.tools.ant.helper.DefaultExecutor.execut eTargets(DefaultExecutor.java:40)
at
org.eclipse.ant.internal.ui.antsupport.EclipseDefa ultExecutor.executeTargets(EclipseDefaultExecutor. java:32)
at org.apache.tools.ant.Project.executeTargets(Projec t.java:1068)
at
org.eclipse.ant.internal.ui.antsupport.InternalAnt Runner.run(InternalAntRunner.java:423)
at
org.eclipse.ant.internal.ui.antsupport.InternalAnt Runner.main(InternalAntRunner.java:137)

Thanks in advance.