The NK 3.3 practicalities documentation recommends that you place NK 3.3 endorsed XML JARs into the installation directory of your JDK (in this case 1.5.0_05):

http://docs.1060.org/docs/3.3.0/book/tutorial/doc_tutorial_fundamentals_practicalities.html

The instructions should be slightly updated to include copying the serializer.jar as well as the other XML JARS. Without serializer.jar NK 3.3 still starts up but it may exhibit runtime issues.