wlappc targets throwing Error

I had been using wlappc targets in WL Portal 9.2 and we made effort to move to
WL Portal 10.0 MP1. Suddenly wlappc did not work. It started throwing errors:

[pre]
weblogic.utils.compiler.ToolFailureException: [J2EE:160141]Could not initialize
the library Extension-Name: wlp-webdav-web-lib, S
pecification-Version: 10, Implementation-Version: 10.0.1. Please ensure the
deployment unit is a valid library type (war
, ejb, ear, plain jar). weblogic.application.library.LibraryProcessingException:
java.io.IOException
        at
weblogic.servlet.internal.WarLibraryDefinition.initDescriptors(WarLibraryDefinit
ion.java:208)
        at
weblogic.servlet.internal.WarLibraryDefinition.init(WarLibraryDefinition.java:13
6)
        at
weblogic.application.utils.LibraryLoggingUtils.initLibraryDefinition(LibraryLogg
ingUtils.java:248)
        at
weblogic.application.library.LibraryInitializer.initRegisteredLibraries(LibraryI
nitializer.java:105)
        at
weblogic.application.compiler.flow.InitLibrariesFlow.compile(InitLibrariesFlow.j
ava:65)
        at
weblogic.application.compiler.FlowDriver$FlowStateChange.next(FlowDriver.java:69
)
        at
weblogic.application.utils.StateMachineDriver.nextState(StateMachineDriver.java:
26)
        at
weblogic.application.compiler.FlowDriver.nextState(FlowDriver.java:36)
        at weblogic.application.compiler.FlowDriver.run(FlowDriver.java:26)
        at weblogic.application.compiler.Appc.runBody(Appc.java:177)
        at weblogic.utils.compiler.Tool.run(Tool.java:158)
        at weblogic.utils.compiler.Tool.run(Tool.java:115)
        at weblogic.application.compiler.Appc.main(Appc.java:188)
        at weblogic.appc.main(appc.java:14)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.jav
a:25)
        at java.lang.reflect.Method.invoke(Method.java:585)
        at
weblogic.ant.taskdefs.j2ee.CompilerTask.invokeMain(CompilerTask.java:290)
        at weblogic.ant.taskdefs.j2ee.Appc.privateExecute(Appc.java:250)
        at weblogic.ant.taskdefs.j2ee.Appc.execute(Appc.java:159)
        at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:275)
        at org.apache.tools.ant.Task.perform(Task.java:364)
        at org.apache.tools.ant.Target.execute(Target.java:341)
        at org.apache.tools.ant.Target.performTasks(Target.java:369)
        at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1216)
        at
org.apache.tools.ant.helper.SingleCheckExecutor.executeTargets(SingleCheckExecut
or.java:37)
        at org.apache.tools.ant.Project.executeTargets(Project.java:1068)
        at org.apache.tools.ant.taskdefs.Ant.execute(Ant.java:382)
        at
org.apache.tools.ant.taskdefs.CallTarget.execute(CallTarget.java:107)
        at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:275)
        at org.apache.tools.ant.Task.perform(Task.java:364)
        at org.apache.tools.ant.Target.execute(Target.java:341)
        at org.apache.tools.ant.Target.performTasks(Target.java: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.executeTargets(DefaultExecutor.java:
40)
        at org.apache.tools.ant.Project.executeTargets(Project.java:1068)
        at org.apache.tools.ant.Main.runBuild(Main.java:668)
        at org.apache.tools.ant.Main.startAnt(Main.java:187)
        at org.apache.tools.ant.launch.Launcher.run(Launcher.java:246)
        at org.apache.tools.ant.launch.Launcher.main(Launcher.java:67)
Caused by: java.io.IOException
        at
weblogic.descriptor.internal.MarshallerFactory.<init>(MarshallerFactory.ja
va:50)
        at
weblogic.descriptor.BasicDescriptorManager.getMarshallerFactory(BasicDescriptorM
anager.java:131)
        at
weblogic.descriptor.BasicDescriptorManager.getDescriptorFactory(BasicDescriptorM
anager.java:165)
        at
weblogic.descriptor.BasicDescriptorManager.createDescriptor(BasicDescriptorManag
er.java:289)
        at
weblogic.descriptor.BasicDescriptorManager.createDescriptor(BasicDescriptorManag
er.java:260)
        at
weblogic.application.descriptor.AbstractDescriptorLoader2.getDescriptorBeanFromR
eader(AbstractDescriptorLoade
r2.java:774)
        at
weblogic.application.descriptor.AbstractDescriptorLoader2.createDescriptorBean(A
bstractDescriptorLoader2.java
:395)
        at
weblogic.application.descriptor.AbstractDescriptorLoader2.loadDescriptorBeanWith
outPlan(AbstractDescriptorLoa
der2.java:745)
        at
weblogic.application.descriptor.AbstractDescriptorLoader2.loadDescriptorBean(Abs
tractDescriptorLoader2.java:7
54)
        at
weblogic.servlet.internal.WebAppDescriptor.getWeblogicWebAppBean(WebAppDescripto
r.java:164)
        at
weblogic.servlet.internal.WarLibraryDefinition.initDescriptors(WarLibraryDefinit
ion.java:201)
        ... 41 more
Caused by: com.bea.xml.XmlException: unable to load type library from
classloader org.apache.tools.ant.loader.AntClassLo
ader2@52f8d7
        at
com.bea.staxb.runtime.internal.BindingContextFactoryImpl.createBindingContext(Bi
ndingContextFactoryImpl.java:
50)
        at
weblogic.descriptor.internal.MarshallerFactory.<init>(MarshallerFactory.ja
va:48)
        ... 51 more
[/pre]

The Error indicated that WLAPPC is complaining about one of the shared libraries
which it binds for compilation.

I was scratching my head around this for hours and hours. Finally worked out a
silly mistake. This target requires weblogic.jar in classpath before the target
can be invoked.

Silly for BEA WebLogic to give irrelevant error message than some
ClassNotFoundException internally.

I wanted to post this so in case if someone is scratching their head, you a