Hey,
I'm having problems with OSX 10.4.4 and libdav (what mod_dav is called on Gentoo) on Apache 1.3.31. I have followed the instructions with only the system-specific modifications, but when I try to connect from Finder in OS X 10.4.4 it asks me for my username/password, then I get a message telling me "You cannot connect to this server because it cannot be found on the network. Try again later or try a different server." I tried switching to basic auth with the same results. Just to be sure it wasen't something funky with Apache, I logged in with DAVExplorer (which worked fine). If I disable authentication, I can login fine.