linkage error

Following the tutorial in the welcome pages productes

java.lang.LinkageError: loader constraint violation: when resolving method "org.apache.log4j.spi.LoggingEvent.(Ljava/lang/String;Lorg/apache/log4j/Category;Lorg/apache/log4j/Priority;Ljava/lang/Object;Ljava/lang/Throwable;)V" the class loader (instance of java/net/FactoryURLClassLoader) of the current class, org/apache/log4j/Category, and the class loader (instance of org/eclipse/osgi/internal/loader/EquinoxClassLoader) for the method's defining class, org/apache/log4j/spi/LoggingEvent, have different Class objects for the type org/apache/log4j/Category used in the signature

when trying to preview the report.

New project with nothing else in it but the files:

Coffee.jrxml

coffee.jpg

Coffee.jasper

coffee_stain.png

I've tried it 3 times now.

1. In an existing project

2. In a new project

3. In a 2nd new project.

Simply follow the steps in the tutorial to reproduce it seems.