I really do not know what to do next.
I have a Bluehost server.
MySQL version 5.1.1945-log
PHP Version 05/02/1911
. Htaccess file is writeable
safe mode off
magic_quotes off
I uploaded Zenphoto 1.2.9 to my web directory and extract.
But i only get a message:
[An error occurred while processing this directive]
I really dont know what it is for with this.
Please help

You have really read this? http://www.zenphoto.org/2008/08/installation-and-upgrading/#1

I am on Bluehost and get the same error when upgrading. I have read the upgrading guide. My zp-core is set to 755. setup.php was unable to create an htaccess file, so I copied it manually. Now I can't even open setup.php. All I get is:
[An error occurred while processing this directive]

OK, I figured it out...

My mistake was hitting the "OK" button before creating the .htaccess file manually.

I restored a backup of my database, started over from scratch with a good htaccess file, and everything worked...

I've read the link above and hit the "OK" button before creating the .htaccess file manually as advised by bigbri, but I still don't know why I keep getting the "[An error occurred while processing this directive]" error. I did everything from backing up my SQL server to setup. Still am receiving the error. I'm desperate..please help.

[i]I've read the link above and hit the "OK" button before creating the .htaccess file manually as advised by bigbri,[/i]
You did not read correctly. First htaccess, then hit OK.