For you, the password is wrong. Swap the c & z and it should work (cz -> zc). If your buddy is fithline then that account isn't validated yet.
If you are using a nightly build then multi.cfg shouldn't be required unless you want to change the default values. If the multi.cfg file is missing, from retail, or configured for FS2NetD, then it will use the default PXO setup automatically.