Publish Clover PHP Coverage Report is checked
Clover XML Location is filled with a valid path
Publish HTML Report isn't checked

ATTENTION: Publisher org.jenkinsci.plugins.cloverphp.CloverPublisher aborted due to exception
java.lang.NullPointerException
at hudson.FilePath.isAbsolute(FilePath.java:228)
at hudson.FilePath.<init>(FilePath.java:216)
at hudson.FilePath.child(FilePath.java:923)
at org.jenkinsci.plugins.cloverphp.CloverPublisher.perform(CloverPublisher.java:162)
at hudson.tasks.BuildStepMonitor$3.perform(BuildStepMonitor.java:36)
at hudson.model.AbstractBuild$AbstractRunner.perform(AbstractBuild.java:694)
at hudson.model.AbstractBuild$AbstractRunner.performAllBuildSteps(AbstractBuild.java:669)
at hudson.model.AbstractBuild$AbstractRunner.performAllBuildSteps(AbstractBuild.java:647)
at hudson.model.Build$RunnerImpl.post2(Build.java:162)
at hudson.model.AbstractBuild$AbstractRunner.post(AbstractBuild.java:616)
at hudson.model.Run.run(Run.java:1429)
at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:46)
at hudson.model.ResourceController.execute(ResourceController.java:88)
at hudson.model.Executor.run(Executor.java:230)

To fix this I checked Publish HTML Report and filled the report directory.