1. knime-core-util.jar is signed but knime-core.jar not. 
   This might lead to an exception thrown by the class loader. Just remove MANIFEST.Mf from
   knime-core-util.jar with
   
   zip -d knime-core-util.jar META-INF/MANIFEST.MF

2. All Eclipse JAR files are needed for running a KNIME Node stand alone.