Carbon Emacs and Samba shares
Lastly I tried to access files on a Samba share (running on a Debian machine) from Carbon Emacs running on Snow Leopard. The files where in a git-repo, so vc-git tried to do his stuff. This made Carbon Emacs hang while creating .#file.pm linked files. flymake had the same issue. So instead of disabling vc-git and flymake, I searched the internet.
The problem got solved by adding this line to the [global] part of the smb.conf file:
unix extensions = no