There seems to be a problem with the getProject method, when i call getProject a
nullpointer is thrown.
In this message you find the code i am using and the stacktrace

public void doCheckDirectory(StaplerRequest req, StaplerResponse rsp,
@QueryParameter
final String value) throws IOException, ServletException {
new FormFieldValidator.WorkspaceFilePath(req, rsp, true, true) {
protected void check() throws IOException, ServletException {
System.out.println("checking");
try

{ AbstractProject b = this.getProject(); }

catch (Exception e)

{ error("exception " + e.getMessage()); e.printStackTrace(); }

}
}.process();
}

checking
java.lang.NullPointerException
at java.util.StringTokenizer.<init>(Unknown Source)
at java.util.StringTokenizer.<init>(Unknown Source)
at hudson.model.Hudson.getItemByFullName(Hudson.java:1229)
at
hudson.util.FormFieldValidator$WorkspaceFilePath.getProject(FormFieldValidator.java:399)
at hudson.plugins.qseplugin.QSETask$QSEDescriptor$2.check(QSETask.java:230)
at hudson.util.FormFieldValidator.process(FormFieldValidator.java:77)
at
hudson.plugins.qseplugin.QSETask$QSEDescriptor.doCheckDirectory(QSETask.java:225)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.kohsuke.stapler.Function$InstanceFunction.invoke(Function.java:146)
at org.kohsuke.stapler.Function.bindAndinvoke(Function.java:71)
at org.kohsuke.stapler.MetaClass$1.doDispatch(MetaClass.java:75)
at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:30)
at org.kohsuke.stapler.Stapler.invoke(Stapler.java:409)
at org.kohsuke.stapler.MetaClass$6.doDispatch(MetaClass.java:173)
at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:30)
at org.kohsuke.stapler.Stapler.invoke(Stapler.java:409)
at org.kohsuke.stapler.Stapler.invoke(Stapler.java:352)
at org.kohsuke.stapler.Stapler.service(Stapler.java:112)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:61)
at hudson.util.PluginServletFilter.doFilter(PluginServletFilter.java:53)
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at hudson.security.HudsonFilter.doFilter(HudsonFilter.java:88)
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:433)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:845)
at
org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Unknown Source)