Root cause is:

java.lang.NullPointerException
hudson.util.FormFieldValidator$WorkspaceFileMask.<init>(FormFieldValidator.java:286)
hudson.util.FormFieldValidator$WorkspaceFileMask.<init>(FormFieldValidator.java:281)
hudson.plugins.tasks.util.PluginDescriptor.doCheckPattern(PluginDescriptor.java:91)
sun.reflect.GeneratedMethodAccessor317.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
java.lang.reflect.Method.invoke(Method.java:597)
org.kohsuke.stapler.Function$InstanceFunction.invoke(Function.java:146)
org.kohsuke.stapler.Function.bindAndinvoke(Function.java:71)
org.kohsuke.stapler.MetaClass$1.doDispatch(MetaClass.java:75)
org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:30)
org.kohsuke.stapler.Stapler.invoke(Stapler.java:409)
org.kohsuke.stapler.MetaClass$6.doDispatch(MetaClass.java:173)
org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:30)
org.kohsuke.stapler.Stapler.invoke(Stapler.java:409)
org.kohsuke.stapler.Stapler.invoke(Stapler.java:352)
org.kohsuke.stapler.Stapler.service(Stapler.java:112)

Which version of hudson and the task scanner plug-in are you using? Seems that
both versions don't match. Could you please upgrade both the the latest version
and retry?

Ok, I have just reinstall hudson from start using last binaries.
Now, I see the same error for cobertura plugin on maven2 project when editing
its configuration.

Thanks.

javax.servlet.ServletException: java.lang.NullPointerException
org.kohsuke.stapler.Stapler.invoke(Stapler.java:450)
org.kohsuke.stapler.MetaClass$6.doDispatch(MetaClass.java:181)
org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:30)
org.kohsuke.stapler.Stapler.invoke(Stapler.java:438)
org.kohsuke.stapler.Stapler.invoke(Stapler.java:356)
org.kohsuke.stapler.Stapler.service(Stapler.java:116)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:68)

root is:

java.lang.NullPointerException
hudson.plugins.cobertura.CoberturaProjectAction.<init>(CoberturaProjectAction.java:27)
hudson.plugins.cobertura.MavenCoberturaPublisher.getProjectAction(MavenCoberturaPublisher.java:198)
hudson.maven.MavenModule.addTransientActionsFromBuild(MavenModule.java:373)
hudson.maven.MavenModule.addTransientActionsFromBuild(MavenModule.java:45)
hudson.maven.AbstractMavenProject.updateTransientActions(AbstractMavenProject.java:33)
hudson.maven.MavenModuleSet.updateTransientActions(MavenModuleSet.java:156)
hudson.model.AbstractProject.submit(AbstractProject.java:1023)
hudson.maven.MavenModuleSet.submit(MavenModuleSet.java:541)
hudson.model.Job.doConfigSubmit(Job.java:858)

And the exception of the tasks plug-in is gone?

Yes but the error on Cobertura plugin seems to have the same cause, no ?

Hmm, even the cobertura plug-in works on my machine...

What kind of job are you using, freestyle with maven or native m2?

Sorry, it appears sometimes when submitting the configuration form of a maven2
project.
I use JBoss 4.2 to run hudson, encapsulated in an ear file to define the web
context name.

Do you have still problems with a more recent version o Hudson. I'm unsure what
to do with this issue? Is this now a problem in the cobertura plug-in?

Hi,

No problem using last release of Hudson. You can close the defect.

Thanks.

Best regards.

Seems to be fixed.