I just had the same problem installing wp on my home machine (OS x 10.2.8), partly having to do with upgrading to php 4.3.4 which seemed to break all my .htaccess files. Here’s how I fixed it.
1. If you haven’t created a .htaccess file, do so for the directories wp-admin and the wproot directory. It should just contain one line:
DirectoryIndex index.php
which tells the web server that when it receives a request for a the directory with no file, to use the file given in the .htaccess file.
I was still getting errors but found this thread:
https://www.webmasterworld.com/forum92/2008.htm
Basicially I had to edit my apache configuration file (look for httpd.conf) to read:
# This controls which options the .htaccess files in directories can
# override. Can also be “All”, or any combination of “Options”, “FileInfo”,
# “AuthConfig”, and “Limit”
#
AllowOverride All
which had been set to ‘None’ previous to upgrading php. You may not need this step. If you modify httpd.conf you need to restart apache.
