I had configured the hostfile located at ~prefix/etc/openmpi-default-hostfile.
I copied the file to bernie-3, and it worked... Now, at the cluster I was working at the Universidad de Los Andes (Venezuela) -I decided to install mpi on three machines I was able to put together as a personal proyect- all I had to do was to compile and run my applications, that is, I never copied any file to any other machine... now, I had to. I'm sorry if it was obvious and made you guys loose some time, but why on a cluster I didn't have to copy any files, and now I must do so? Thanks for you patiance! Jose