I couldn't find any links to bug trackers from the main site. If there is a different procedure for reporting bugs, please let me know.
The Linux and Windows versions have the equivalent of (in pseudo-.conf):
<Directory "...htdocs">
AllowOverride All
</Directory>
But the Macintosh version has:
<Directory "...htdocs">
AllowOverride AuthConfig
</Directory>
This means Drupal works out of the box with LAMPP and WAMPP, but not with MAMPP. Probably other applications are affected too. See this thread:
http://drupal.org/node/291669#comment-979545
(I have posted there as davcamer)