I couldn't post this in the other thread because it's closed.
http://www.kriesi.at/support/topic/front-page-disappeared-turned-to-black
The problems demozeno was having might be MAMP related. SInce it's an offline emulator it's very hard to know how it was set up, but I use it sometimes and there are a couple of things I had to correct to solve some problems.
1. Give the php more memory. It's set in MAMP to be about 32MB. Put it up to at least 64MB
2. Make all the permissions writeable and readable (basically tick all the check boxes)
When you go from MAMP to the online site, it's very important to remember to change all the offline urls to the online ones, and tell the database file to rename all its internal links also.
You have to change your wp-config.php settings, change any urls in any .css or .php files that have been custom modified, and most importantly correctly export, reconfigure and import the database file into the new site with the internal links amended (the database file is a .sql file that you export using phpmyadmin). You can do it with a search/replace in any text editor but the tool below does a much better job on big databases.
When your exported database file gets near 10mb you may have to import it using the terminal as phpmyadmin doesn't like big files.
This tool is really handy to import your database files correctly: searchreplacedb.php. You can get it from here:
http://interconnectit.com/719/migrating-a-wordpresswpmubuddypress-website/














