I got the same problem on Linux with 1.252. It's because the StringUtils.join
method used in tasks 2.17 was introduced in commons lang 2.3 but hudson.war only
packages the 2.1 version. It looks like that jar is loaded and
commons-lang-2.3.jar included in tasks.hpi is ignored.

Same situation here:

[TASKS] Scanning workspace files for tasks...
FATAL:
org.apache.commons.lang.StringUtils.join(Ljava/util/Collection;Ljava/lang/String;)Ljava/lang/String;
java.lang.NoSuchMethodError:
org.apache.commons.lang.StringUtils.join(Ljava/util/Collection;Ljava/lang/String;)Ljava/lang/String;
at hudson.plugins.tasks.parser.TaskScanner.compile(TaskScanner.java:87)
at hudson.plugins.tasks.parser.TaskScanner.<init>(TaskScanner.java:49)
at hudson.plugins.tasks.parser.WorkspaceScanner.invoke(WorkspaceScanner.java:116)
at hudson.plugins.tasks.parser.WorkspaceScanner.invoke(WorkspaceScanner.java:29)
at hudson.FilePath.act(FilePath.java:363)
at hudson.plugins.tasks.TasksPublisher.perform(TasksPublisher.java:140)
at hudson.plugins.tasks.TasksPublisher.perform(TasksPublisher.java:24)
at
hudson.plugins.tasks.util.HealthAwarePublisher.perform(HealthAwarePublisher.java:169)
at
hudson.model.AbstractBuild$AbstractRunner.performAllBuildStep(AbstractBuild.java:318)
at
hudson.model.AbstractBuild$AbstractRunner.performAllBuildStep(AbstractBuild.java:306)
at hudson.model.Build$RunnerImpl.post2(Build.java:126)
at hudson.model.AbstractBuild$AbstractRunner.post(AbstractBuild.java:291)
at hudson.model.Run.run(Run.java:813)
at hudson.model.Build.run(Build.java:88)
at hudson.model.ResourceController.execute(ResourceController.java:70)
at hudson.model.Executor.run(Executor.java:88)

This is releated to issue 1409.

I will downgrade the dependency to commons lang 2.1

Code changed in hudson
User: : drulli
Path:
trunk/hudson/plugins/tasks/.classpath
trunk/hudson/plugins/tasks/.project
trunk/hudson/plugins/tasks/pom.xml
trunk/hudson/plugins/tasks/src/main/java/hudson/plugins/tasks/parser/TaskScanner.java
http://fisheye4.cenqua.com/changelog/hudson/?cs=12131
Log:
[FIXED JENKINS-2369] Downgrade to Jakarta commons lang 2.1, which is also used by Hudson core.