[JAVA3D] installation problem

[Aant]

when i try to run a app i get the errormessage: "java.lang.NoClassDefFoundError: javax/media/j3d/Group" I have java2 sdk standard edition 1.3 and java3d 1.1.3 (opengl version) on my pc What must i do so i can use java3D with java2 in app's