This was a great help in tracking down my problem! My environment is OS X 10.4.6 with Apache 1.3.
I am trying to get multiple Rails applications running under FCGI. I have elected (for now) to use Dynamic FCGI. I was getting "Permission denied: FastCGI: can't create (dynamic) server "/Users/Jonathan/Development/LocoProjects/Wine/public/dispatch.fcgi": bind() failed [/tmp/fcgi_ipc/dynamic/d29d7200146ea5e733d8dea665329310]"
It turns out that I also needed to change the permissions for the dynamic directory as well with:
chmod 777 /tmp/fcgi_ipc/dynamic
Hope this helps someone else.