I get the ClassCastException on trying to run test from jenkins through testlink plugin .Looks like this is an issue similar to JENKINS-17442 but plugin version 3.9.
FATAL: [Ljava.lang.Object; cannot be cast to java.util.Map
java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to java.util.Map
at br.eti.kinoshita.testlinkjavaapi.util.Util.castToMap(Util.java:591)
at br.eti.kinoshita.testlinkjavaapi.TestProjectService.getTestProjectByName(TestProjectService.java:115)
at br.eti.kinoshita.testlinkjavaapi.TestLinkAPI.getTestProjectByName(TestLinkAPI.java:438)
at hudson.plugins.testlink.TestLinkBuilder.getTestLinkSite(TestLinkBuilder.java:309)
at hudson.plugins.testlink.TestLinkBuilder.perform(TestLinkBuilder.java:186)
at hudson.tasks.BuildStepMonitor$1.perform(BuildStepMonitor.java:20)
at hudson.model.AbstractBuild$AbstractBuildExecution.perform(AbstractBuild.java:785)
at hudson.model.Build$BuildExecution.build(Build.java:199)
at hudson.model.Build$BuildExecution.doRun(Build.java:160)
at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:566)
at hudson.model.Run.execute(Run.java:1678)
at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:46)
at hudson.model.ResourceController.execute(ResourceController.java:88)
at hudson.model.Executor.run(Executor.java:231)