(Deleted by the Author)
I think I saw that as well. Irrisor added some stuff for me and it showed up then. I havn't had time to even look at it though.
I have the same error, with the same installing system/software specs. So it seems to be a general issue. 
Edit: It looks to me as if the class is trying to use a method (org.odejava.org.Ode.dMassSetTrimesh) that is not present in the odejava-jni.jar file provided with the checked out jMEPhysics project.
Sorry guys - fixed in CVS