Looks like this problem has been reported before, but I'm too sure if a solution was ever found.
As soon as I modify the db.ini file, i get the error: 'No such file or directory'.
I'm running snow leopard and have all the required up to date technologies installed locally minus ImageMagick.
I'm running MySQL 5.1.38
Just curious if you guys ever came up with a solution.
I'm not sure which forum post you are speaking of specifically since you have not replied directly on it, but there are a couple of posts related to running Omeka locally that might help.
(FYI, you will need ImageMagick if you plan to display images in your Omeka site.)