Zenphoto is installed in /
I have other scripts installed in subfolders. For example, a blog scripts in /ssblog.

The problem is when I have the htaccess file with modrewrite, it effects the entire site.
So, if I try to access a script, http://www.mysite.com/ssblog/index.php I get the follow error:

The image index.php does not exist.

An .htaccess file will affect the currect directory as well as all subdirectories. To not have the changes put in the sub-directories, you need to put a seperate .htaccess file into those directories with the rules you need.

Here's a good guide I've been reading: http://www.javascriptkit.com/howto/htaccess.shtml

Are you using the newest version with the newest .htaccess (1.0.2)? This problem should be fixed with it... if it's not, I'd like to hear more...

Ah, this was a bit ago. Try upgrading!