try to push angular JS app (unzipped directory) and getting following error

java.lang.IllegalStateException: Unzipped output directory was empty.
at com.hpe.cloudfoundryjenkins.CloudFoundryPushPublisher.pushAppBits(CloudFoundryPushPublisher.java:415)
at com.hpe.cloudfoundryjenkins.CloudFoundryPushPublisher.processOneApp(CloudFoundryPushPublisher.java:272)
at com.hpe.cloudfoundryjenkins.CloudFoundryPushPublisher.perform(CloudFoundryPushPublisher.java:188)
at hudson.tasks.BuildStepMonitor$1.perform(BuildStepMonitor.java:20)
at hudson.model.AbstractBuild$AbstractBuildExecution.perform(AbstractBuild.java:782)
at hudson.model.AbstractBuild$AbstractBuildExecution.performAllBuildSteps(AbstractBuild.java:723)
at hudson.model.Build$BuildExecution.post2(Build.java:185)
at hudson.model.AbstractBuild$AbstractBuildExecution.post(AbstractBuild.java:668)
at hudson.model.Run.execute(Run.java:1763)
at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:43)
at hudson.model.ResourceController.execute(ResourceController.java:98)
at hudson.model.Executor.run(Executor.java:410)
Build step 'Push to Cloud Foundry' marked build as failure